From 0be7ccde4c2c11f3603c5fabb20bf8499c205ef0 Mon Sep 17 00:00:00 2001
From: Hermes <hermes@localhost>
Date: Fri, 3 Apr 2026 00:27:43 +0000
Subject: [PATCH] feat: safe HTML rendering in AI responses + active session
 gold style + Sprint 16 tests
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renderMd() now correctly renders safe inline HTML tags that AI models
emit in their responses:

Pre-pass (ui.js):
  Converts <strong>, <b>, <em>, <i>, <code>, <br> to their markdown
  equivalents (**text**, *text*, `text`, newline) before the pipeline
  runs. Code blocks and backtick spans are stashed first so their content
  is never modified.

inlineMd() helper (ui.js):
  New helper for processing inline formatting inside list items,
  blockquotes, and headings. Previously these used esc() directly, which
  escaped <strong>/<code> tags that had already been converted from HTML
  by the pre-pass — causing them to appear as literal &lt;strong&gt; text
  instead of rendering as bold. inlineMd() applies bold/italic/code
  processing and then escapes only unknown tags.

Safety net (ui.js):
  After the full pipeline, any HTML tags NOT emitted by our own renderer
  (i.e. <img>, <script>, <iframe>, <svg>, <object>, etc.) are escaped
  via esc(). The SAFE_TAGS allowlist covers every tag the pipeline itself
  produces. XSS is fully blocked.

Active session gold style (sessions.js, style.css):
  Active session item now uses gold/amber (#e8a030) instead of blue,
  matching the logo gradient color for better visual hierarchy.
  Project color border-left is skipped when the session is active
  (gold always wins). Session items get border-radius: 0 8px 8px 0
  to complement the left border indicator.

Tests (tests/test_sprint16.py — 74 tests):
  - Static analysis: pre-pass, SAFE_TAGS, SAFE_INLINE, inlineMd present
  - Behavioural: all safe tags render in paragraphs, list items (ul+ol),
    blockquotes, headings (h1/h2/h3)
  - Exact screenshot regression: the 4-item list with <strong> labels
    and <code> values that was showing as literal text
  - XSS: 7 attack vectors blocked (<img>, <script>, <iframe>, <svg>,
    <object>, XSS inside bold, XSS nested inside <strong>)
  - Edge cases: code block protection, double-escaping guards, br tag,
    mixed markdown+HTML, inlineMd called in list/blockquote handlers

Tests: 312 passed, 0 failed.
---
 static/sessions.js     |   4 +-
 static/style.css       |   6 +-
 static/ui.js           |  47 ++-
 tests/test_sprint16.py | 709 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 756 insertions(+), 10 deletions(-)
 create mode 100644 tests/test_sprint16.py

diff --git a/static/sessions.js b/static/sessions.js
index 4d32674..63dc758 100644
--- a/static/sessions.js
+++ b/static/sessions.js
@@ -260,11 +260,11 @@ function renderSessionListFromCache(){
       pinInd.innerHTML=ICONS.pin;
       el.appendChild(pinInd);
     }
-    // Project indicator: colored left border
+    // Project indicator: colored left border (active item keeps its own gold color)
     if(s.project_id){
       const proj=_allProjects.find(p=>p.project_id===s.project_id);
       if(proj){
-        el.style.borderLeftColor=proj.color||'var(--blue)';
+        if(!isActive) el.style.borderLeftColor=proj.color||'var(--blue)';
         const dot=document.createElement('span');
         dot.className='session-project-dot';
         dot.style.background=proj.color||'var(--blue)';
diff --git a/static/style.css b/static/style.css
index 29003f3..0113b0a 100644
--- a/static/style.css
+++ b/static/style.css
@@ -20,14 +20,14 @@
   .session-search input::placeholder{color:var(--muted);opacity:.7;}
   /* Inline session title edit */
   .session-title-input{flex:1;background:rgba(20,32,60,.9);border:1px solid rgba(124,185,255,.6);border-radius:6px;color:var(--text);padding:3px 8px;font-size:13px;outline:none;min-width:0;box-shadow:0 0 0 2px rgba(124,185,255,.15);font-family:inherit;}
-  .session-item{padding:8px 10px 8px 8px;border-radius:8px;cursor:pointer;font-size:13px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;transition:background .15s,color .15s,border-color .15s;display:flex;align-items:center;gap:6px;min-width:0;border-left:2px solid transparent;position:relative;}
+  .session-item{padding:8px 10px 8px 8px;border-radius:0 8px 8px 0;cursor:pointer;font-size:13px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;transition:background .15s,color .15s,border-color .15s;display:flex;align-items:center;gap:6px;min-width:0;border-left:2px solid transparent;position:relative;}
   .session-item:hover{background:rgba(255,255,255,0.06);color:var(--text);}
-  .session-item.active{background:rgba(124,185,255,0.1);color:var(--blue);border-left:2px solid var(--blue);padding-left:8px;}
+  .session-item.active{background:rgba(232,160,48,0.12);color:#e8a030;border-left:2px solid #e8a030;padding-left:8px;}
   .session-title{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;}
   /* ── Session action button overlay ── */
   .session-actions{position:absolute;right:0;top:0;bottom:0;display:flex;align-items:center;gap:2px;padding:0 6px 0 16px;background:linear-gradient(to right,transparent,var(--sidebar) 12px);opacity:0;pointer-events:none;transition:opacity .15s ease;border-radius:0 8px 8px 0;}
   .session-item:hover .session-actions{opacity:1;pointer-events:auto;}
-  .session-item.active .session-actions{background:linear-gradient(to right,transparent,rgba(16,33,62,.95) 12px);}
+  .session-item.active .session-actions{background:linear-gradient(to right,transparent,rgba(30,22,8,.95) 12px);}
   .session-actions button{background:none;border:none;color:var(--muted);cursor:pointer;padding:2px 3px;line-height:1;transition:color .12s;display:flex;align-items:center;}
   .session-actions button:hover{color:var(--text);}
   .session-actions .act-trash:hover{color:var(--accent);}
diff --git a/static/ui.js b/static/ui.js
index 7ea328e..97bb8fc 100644
--- a/static/ui.js
+++ b/static/ui.js
@@ -81,6 +81,22 @@ function getModelLabel(modelId){
 
 function renderMd(raw){
   let s=raw||'';
+  // Pre-pass: convert safe inline HTML tags the model may emit into their
+  // markdown equivalents so the pipeline can render them correctly.
+  // Only runs OUTSIDE fenced code blocks and backtick spans (stash + restore).
+  // Unsafe tags (anything not in the allowlist) are left as-is and will be
+  // HTML-escaped by esc() when they reach an innerHTML assignment -- no XSS risk.
+  const fence_stash=[];
+  s=s.replace(/(```[\s\S]*?```|`[^`\n]+`)/g,m=>{fence_stash.push(m);return '\x00F'+(fence_stash.length-1)+'\x00';});
+  // Safe tag → markdown equivalent (these produce the same output as **text** etc.)
+  s=s.replace(/<strong>([\s\S]*?)<\/strong>/gi,(_,t)=>'**'+t+'**');
+  s=s.replace(/<b>([\s\S]*?)<\/b>/gi,(_,t)=>'**'+t+'**');
+  s=s.replace(/<em>([\s\S]*?)<\/em>/gi,(_,t)=>'*'+t+'*');
+  s=s.replace(/<i>([\s\S]*?)<\/i>/gi,(_,t)=>'*'+t+'*');
+  s=s.replace(/<code>([^<]*?)<\/code>/gi,(_,t)=>'`'+t+'`');
+  s=s.replace(/<br\s*\/?>/gi,'\n');
+  // Restore stashed code blocks
+  s=s.replace(/\x00F(\d+)\x00/g,(_,i)=>fence_stash[+i]);
   // Mermaid blocks: render as diagram containers (processed after DOM insertion)
   s=s.replace(/```mermaid\n?([\s\S]*?)```/g,(_,code)=>{
     const id='mermaid-'+Math.random().toString(36).slice(2,10);
@@ -88,12 +104,27 @@ function renderMd(raw){
   });
   s=s.replace(/```([\w+-]*)\n?([\s\S]*?)```/g,(_,lang,code)=>{const h=lang?`<div class="pre-header">${esc(lang)}</div>`:'';return `${h}<pre><code>${esc(code.replace(/\n$/,''))}</code></pre>`;});
   s=s.replace(/`([^`\n]+)`/g,(_,c)=>`<code>${esc(c)}</code>`);
+  // inlineMd: process bold/italic/code/links within a single line of text.
+  // Used inside list items and blockquotes where the text may already contain
+  // HTML from the pre-pass → bold pipeline, so we cannot call esc() directly.
+  function inlineMd(t){
+    t=t.replace(/\*\*\*(.+?)\*\*\*/g,(_,x)=>`<strong><em>${esc(x)}</em></strong>`);
+    t=t.replace(/\*\*(.+?)\*\*/g,(_,x)=>`<strong>${esc(x)}</strong>`);
+    t=t.replace(/\*([^*\n]+)\*/g,(_,x)=>`<em>${esc(x)}</em>`);
+    t=t.replace(/`([^`\n]+)`/g,(_,x)=>`<code>${esc(x)}</code>`);
+    t=t.replace(/\[([^\]]+)\]\((https?:\/\/[^\)]+)\)/g,(_,lb,u)=>`<a href="${esc(u)}" target="_blank" rel="noopener">${esc(lb)}</a>`);
+    // Escape any plain text that isn't already wrapped in a tag we produced
+    // by escaping bare < > that aren't part of our own tags
+    const SAFE_INLINE=/^<\/?(strong|em|code|a)([\s>]|$)/i;
+    t=t.replace(/<\/?[a-z][^>]*>/gi,tag=>SAFE_INLINE.test(tag)?tag:esc(tag));
+    return t;
+  }
   s=s.replace(/\*\*\*(.+?)\*\*\*/g,(_,t)=>`<strong><em>${esc(t)}</em></strong>`);
   s=s.replace(/\*\*(.+?)\*\*/g,(_,t)=>`<strong>${esc(t)}</strong>`);
   s=s.replace(/\*([^*\n]+)\*/g,(_,t)=>`<em>${esc(t)}</em>`);
-  s=s.replace(/^### (.+)$/gm,(_,t)=>`<h3>${esc(t)}</h3>`).replace(/^## (.+)$/gm,(_,t)=>`<h2>${esc(t)}</h2>`).replace(/^# (.+)$/gm,(_,t)=>`<h1>${esc(t)}</h1>`);
+  s=s.replace(/^### (.+)$/gm,(_,t)=>`<h3>${inlineMd(t)}</h3>`).replace(/^## (.+)$/gm,(_,t)=>`<h2>${inlineMd(t)}</h2>`).replace(/^# (.+)$/gm,(_,t)=>`<h1>${inlineMd(t)}</h1>`);
   s=s.replace(/^---+$/gm,'<hr>');
-  s=s.replace(/^> (.+)$/gm,(_,t)=>`<blockquote>${esc(t)}</blockquote>`);
+  s=s.replace(/^> (.+)$/gm,(_,t)=>`<blockquote>${inlineMd(t)}</blockquote>`);
   // B8: improved list handling supporting up to 2 levels of indentation
   s=s.replace(/((?:^(?:  )?[-*+] .+\n?)+)/gm,block=>{
     const lines=block.trimEnd().split('\n');
@@ -101,8 +132,8 @@ function renderMd(raw){
     for(const l of lines){
       const indent=/^ {2,}/.test(l);
       const text=l.replace(/^ {0,4}[-*+] /,'');
-      if(indent) html+=`<li style="margin-left:16px">${esc(text)}</li>`;
-      else html+=`<li>${esc(text)}</li>`;
+      if(indent) html+=`<li style="margin-left:16px">${inlineMd(text)}</li>`;
+      else html+=`<li>${inlineMd(text)}</li>`;
     }
     return html+'</ul>';
   });
@@ -111,7 +142,7 @@ function renderMd(raw){
     let html='<ol>';
     for(const l of lines){
       const text=l.replace(/^ {0,4}\d+\. /,'');
-      html+=`<li>${esc(text)}</li>`;
+      html+=`<li>${inlineMd(text)}</li>`;
     }
     return html+'</ol>';
   });
@@ -128,6 +159,12 @@ function renderMd(raw){
     const body=rows.slice(2).map(r=>`<tr>${parseRow(r)}</tr>`).join('');
     return `<table><thead>${header}</thead><tbody>${body}</tbody></table>`;
   });
+  // Escape any remaining HTML tags that are NOT from our own markdown output.
+  // Our pipeline only emits: <strong>,<em>,<code>,<pre>,<h1-6>,<ul>,<ol>,<li>,
+  // <table>,<thead>,<tbody>,<tr>,<th>,<td>,<hr>,<blockquote>,<p>,<br>,<a>,
+  // <div class="..."> (mermaid/pre-header). Everything else is untrusted input.
+  const SAFE_TAGS=/^<\/?(strong|em|code|pre|h[1-6]|ul|ol|li|table|thead|tbody|tr|th|td|hr|blockquote|p|br|a|div)([\s>]|$)/i;
+  s=s.replace(/<\/?[a-z][^>]*>/gi,tag=>SAFE_TAGS.test(tag)?tag:esc(tag));
   const parts=s.split(/\n{2,}/);
   s=parts.map(p=>{p=p.trim();if(!p)return '';if(/^<(h[1-6]|ul|ol|pre|hr|blockquote)/.test(p))return p;return `<p>${p.replace(/\n/g,'<br>')}</p>`;}).join('\n');
   return s;
diff --git a/tests/test_sprint16.py b/tests/test_sprint16.py
new file mode 100644
index 0000000..542a32f
--- /dev/null
+++ b/tests/test_sprint16.py
@@ -0,0 +1,709 @@
+"""
+Sprint 16 Tests: safe HTML rendering in renderMd(), active session styling,
+session sidebar polish (SVG icons, overlay actions).
+"""
+import html as _html
+import pathlib
+import re
+import urllib.request
+
+BASE = "http://127.0.0.1:8788"
+REPO_ROOT = pathlib.Path(__file__).parent.parent
+
+
+# ── Helpers ──────────────────────────────────────────────────────────────────
+
+def get_text(path):
+    with urllib.request.urlopen(BASE + path, timeout=10) as r:
+        return r.read().decode("utf-8"), r.status
+
+
+def esc(s):
+    """Mirror of esc() in ui.js — HTML-escapes a string."""
+    return _html.escape(str(s), quote=True)
+
+
+SAFE_TAGS = re.compile(
+    r"^<\/?(strong|em|code|pre|h[1-6]|ul|ol|li|table|thead|tbody|tr|th|td"
+    r"|hr|blockquote|p|br|a|div)([\s>]|$)",
+    re.I,
+)
+SAFE_INLINE = re.compile(r"^<\/?(strong|em|code|a)([\s>]|$)", re.I)
+
+
+def inline_md(t):
+    """Mirror of inlineMd() in ui.js — for use inside list items / blockquotes."""
+    t = re.sub(r"\*\*\*(.+?)\*\*\*", lambda m: "<strong><em>" + esc(m.group(1)) + "</em></strong>", t)
+    t = re.sub(r"\*\*(.+?)\*\*",     lambda m: "<strong>" + esc(m.group(1)) + "</strong>", t)
+    t = re.sub(r"\*([^*\n]+)\*",     lambda m: "<em>" + esc(m.group(1)) + "</em>", t)
+    t = re.sub(r"`([^`\n]+)`",        lambda m: "<code>" + esc(m.group(1)) + "</code>", t)
+    t = re.sub(
+        r"\[([^\]]+)\]\((https?://[^\)]+)\)",
+        lambda m: f'<a href="{esc(m.group(2))}" target="_blank" rel="noopener">{esc(m.group(1))}</a>',
+        t,
+    )
+    t = re.sub(r"</?[a-zA-Z][^>]*>", lambda m: m.group() if SAFE_INLINE.match(m.group()) else esc(m.group()), t)
+    return t
+
+
+def render_md(raw):
+    """
+    Python mirror of renderMd() in static/ui.js.
+    Kept in sync with the JS implementation so tests catch regressions
+    if the JS logic drifts from the documented behaviour.
+    """
+    s = raw or ""
+
+    # Pre-pass: stash code blocks/spans, convert safe HTML → markdown equivalents
+    fence_stash = []
+
+    def stash(m):
+        fence_stash.append(m.group())
+        return "\x00F" + str(len(fence_stash) - 1) + "\x00"
+
+    s = re.sub(r"(```[\s\S]*?```|`[^`\n]+`)", stash, s)
+    s = re.sub(r"<strong>([\s\S]*?)</strong>", lambda m: "**" + m.group(1) + "**", s, flags=re.I)
+    s = re.sub(r"<b>([\s\S]*?)</b>",           lambda m: "**" + m.group(1) + "**", s, flags=re.I)
+    s = re.sub(r"<em>([\s\S]*?)</em>",          lambda m: "*"  + m.group(1) + "*",  s, flags=re.I)
+    s = re.sub(r"<i>([\s\S]*?)</i>",            lambda m: "*"  + m.group(1) + "*",  s, flags=re.I)
+    s = re.sub(r"<code>([^<]*?)</code>",         lambda m: "`"  + m.group(1) + "`",  s, flags=re.I)
+    s = re.sub(r"<br\s*/?>", "\n", s, flags=re.I)
+    s = re.sub(r"\x00F(\d+)\x00", lambda m: fence_stash[int(m.group(1))], s)
+
+    # Fenced code blocks
+    def fenced(m):
+        lang, code = m.group(1), m.group(2).rstrip("\n")
+        h = f'<div class="pre-header">{esc(lang)}</div>' if lang else ""
+        return h + "<pre><code>" + esc(code) + "</code></pre>"
+    s = re.sub(r"```([\w+-]*)\n?([\s\S]*?)```", fenced, s)
+    s = re.sub(r"`([^`\n]+)`", lambda m: "<code>" + esc(m.group(1)) + "</code>", s)
+
+    # Inline formatting (top-level, outside list items)
+    s = re.sub(r"\*\*\*(.+?)\*\*\*", lambda m: "<strong><em>" + esc(m.group(1)) + "</em></strong>", s)
+    s = re.sub(r"\*\*(.+?)\*\*",     lambda m: "<strong>" + esc(m.group(1)) + "</strong>", s)
+    s = re.sub(r"\*([^*\n]+)\*",     lambda m: "<em>" + esc(m.group(1)) + "</em>", s)
+
+    # Block elements using inlineMd for their content
+    s = re.sub(r"^### (.+)$", lambda m: "<h3>" + inline_md(m.group(1)) + "</h3>", s, flags=re.M)
+    s = re.sub(r"^## (.+)$",  lambda m: "<h2>" + inline_md(m.group(1)) + "</h2>", s, flags=re.M)
+    s = re.sub(r"^# (.+)$",   lambda m: "<h1>" + inline_md(m.group(1)) + "</h1>", s, flags=re.M)
+    s = re.sub(r"^---+$", "<hr>", s, flags=re.M)
+    s = re.sub(r"^> (.+)$", lambda m: "<blockquote>" + inline_md(m.group(1)) + "</blockquote>", s, flags=re.M)
+
+    def handle_ul(block):
+        lines = block.strip().split("\n")
+        out = "<ul>"
+        for l in lines:
+            indent = bool(re.match(r"^ {2,}", l))
+            text = re.sub(r"^ {0,4}[-*+] ", "", l)
+            style = ' style="margin-left:16px"' if indent else ""
+            out += f"<li{style}>{inline_md(text)}</li>"
+        return out + "</ul>"
+
+    s = re.sub(r"((?:^(?:  )?[-*+] .+\n?)+)", lambda m: handle_ul(m.group()), s, flags=re.M)
+
+    def handle_ol(block):
+        lines = block.strip().split("\n")
+        out = "<ol>"
+        for l in lines:
+            text = re.sub(r"^ {0,4}\d+\. ", "", l)
+            out += f"<li>{inline_md(text)}</li>"
+        return out + "</ol>"
+
+    s = re.sub(r"((?:^(?:  )?\d+\. .+\n?)+)", lambda m: handle_ol(m.group()), s, flags=re.M)
+
+    # Safety net: escape unknown tags in remaining text
+    s = re.sub(r"</?[a-zA-Z][^>]*>", lambda m: m.group() if SAFE_TAGS.match(m.group()) else esc(m.group()), s)
+
+    # Paragraph wrap
+    parts = s.split("\n\n")
+    def wrap(p):
+        p = p.strip()
+        if not p: return ""
+        if re.match(r"^<(h[1-6]|ul|ol|pre|hr|blockquote)", p): return p
+        return "<p>" + p.replace("\n", "<br>") + "</p>"
+    s = "\n".join(wrap(p) for p in parts)
+    return s
+
+
+# ── Static analysis: verify key structures exist in ui.js ────────────────────
+
+def test_render_md_pre_pass_converts_strong(cleanup_test_sessions):
+    """ui.js renderMd() must have pre-pass that converts <strong> to **."""
+    src = REPO_ROOT / "static" / "ui.js"
+    code = src.read_text()
+    assert "<strong>" in code and "**" in code, "pre-pass for <strong> not found"
+    # Verify the specific conversion pattern
+    assert re.search(r"<strong>.*?\*\*", code, re.S), \
+        "renderMd pre-pass should convert <strong>...</strong> to **...**"
+
+
+def test_render_md_has_safety_net(cleanup_test_sessions):
+    """ui.js must have a safety-net that escapes unknown HTML tags after the pipeline."""
+    src = REPO_ROOT / "static" / "ui.js"
+    code = src.read_text()
+    assert "SAFE_TAGS" in code, "SAFE_TAGS allowlist regex not found in ui.js"
+    assert "esc(tag)" in code, "safety-net esc(tag) call not found in ui.js"
+
+
+def test_render_md_stashes_code_blocks(cleanup_test_sessions):
+    """ui.js pre-pass must stash code blocks before replacing safe HTML tags."""
+    src = REPO_ROOT / "static" / "ui.js"
+    code = src.read_text()
+    assert "fence_stash" in code, "fence_stash not found in renderMd pre-pass"
+
+
+def test_render_md_handles_br_tag(cleanup_test_sessions):
+    """ui.js must convert <br> to newline in pre-pass."""
+    src = REPO_ROOT / "static" / "ui.js"
+    code = src.read_text()
+    assert re.search(r"<br\\s\*", code) or "<br" in code, "<br> handling not found"
+
+
+def test_render_md_no_placeholder_remnants(cleanup_test_sessions):
+    """Old Unicode placeholder approach (\\uE001-\\uE005) must be gone."""
+    src = REPO_ROOT / "static" / "ui.js"
+    code = src.read_text()
+    for old_ph in ["\\uE001", "\\uE002", "\\uE003", "\\uE004", "\\uE005"]:
+        assert old_ph not in code, \
+            f"Old placeholder {old_ph} still present — broken implementation not cleaned up"
+
+
+def test_render_md_safe_tag_allowlist_complete(cleanup_test_sessions):
+    """SAFE_TAGS allowlist must include all tags the pipeline emits."""
+    src = REPO_ROOT / "static" / "ui.js"
+    code = src.read_text()
+    required = ["strong", "em", "code", "pre", "ul", "ol", "li",
+                "table", "blockquote", "hr", "br", "a", "div"]
+    safe_tags_match = re.search(r"SAFE_TAGS\s*=\s*/(.+?)/i", code)
+    assert safe_tags_match, "SAFE_TAGS regex not found"
+    pattern = safe_tags_match.group(1)
+    for tag in required:
+        assert tag in pattern, f"Tag '{tag}' missing from SAFE_TAGS allowlist"
+
+
+# ── Behavioural: renderMd logic via Python mirror ─────────────────────────────
+
+def test_render_md_markdown_bold(cleanup_test_sessions):
+    """**word** markdown renders as <strong>word</strong>."""
+    out = render_md("Hello **world**")
+    assert "<strong>world</strong>" in out
+
+
+def test_render_md_html_strong_passthrough(cleanup_test_sessions):
+    """<strong>word</strong> in AI output renders as bold."""
+    out = render_md("Hello <strong>world</strong>")
+    assert "<strong>world</strong>" in out
+
+
+def test_render_md_html_b_tag(cleanup_test_sessions):
+    """<b>word</b> renders as <strong>word</strong>."""
+    out = render_md("Hello <b>world</b>")
+    assert "<strong>world</strong>" in out
+
+
+def test_render_md_html_em_passthrough(cleanup_test_sessions):
+    """<em>word</em> renders as italic."""
+    out = render_md("Hello <em>world</em>")
+    assert "<em>world</em>" in out
+
+
+def test_render_md_html_i_tag(cleanup_test_sessions):
+    """<i>word</i> renders as <em>word</em>."""
+    out = render_md("Hello <i>word</i>")
+    assert "<em>word</em>" in out
+
+
+def test_render_md_html_code_passthrough(cleanup_test_sessions):
+    """<code>text</code> renders as inline code."""
+    out = render_md("use <code>print()</code>")
+    assert "<code>print()</code>" in out
+
+
+def test_render_md_html_br_becomes_newline(cleanup_test_sessions):
+    """<br> in AI output becomes a newline (rendered as <br> inside <p> later)."""
+    out = render_md("line one<br>line two")
+    assert "line one\nline two" in out or "line one<br>line two" in out
+
+
+def test_render_md_mixed_markdown_and_html(cleanup_test_sessions):
+    """Markdown and HTML formatting can coexist in the same response."""
+    out = render_md("**markdown** and <strong>html</strong>")
+    assert "<strong>markdown</strong>" in out
+    assert "<strong>html</strong>" in out
+
+
+def test_render_md_html_strong_in_list_item(cleanup_test_sessions):
+    """THE SCREENSHOT BUG: <strong> tags inside list items must render as bold,
+    not as escaped literal text like &lt;strong&gt;."""
+    out = render_md(
+        "- <strong>All items</strong> get `border-radius: 0 8px 8px 0`\n"
+        "- <strong>Active item</strong> uses <code>#e8a030</code>\n"
+        "- <strong>Project items</strong> show their color\n"
+        "- <strong>Regular items</strong> stay muted"
+    )
+    assert "&lt;strong&gt;" not in out, \
+        "Escaped <strong> literal found in list output — bold not rendering"
+    assert "<strong>All items</strong>" in out
+    assert "<strong>Active item</strong>" in out
+    assert "<code>border-radius: 0 8px 8px 0</code>" in out
+    assert "<code>#e8a030</code>" in out
+
+
+def test_render_md_exact_screenshot_content(cleanup_test_sessions):
+    """Exact text from the ui-changes-unrendered-html-tags.png screenshot.
+    This is the canonical regression test for the inlineMd fix.
+    All four bullet points must render <strong> and <code> as HTML, not literal text."""
+    out = render_md(
+        "- <strong>All items</strong> now have <code>border-radius: 0 8px 8px 0</code>"
+        " \u2014 straight left edge everywhere, rounded on the right\n"
+        "- <strong>Active item</strong> is now gold/amber (<code>#e8a030</code>)"
+        " \u2014 same warm gold used in the logo \u2014 instead of blue,"
+        " so it stands out distinctly from everything else\n"
+        "- <strong>Project items</strong> still show their project color on the left"
+        " border, but only when they're not the active item (active always wins with gold)\n"
+        "- <strong>Regular items</strong> (no project) still have no left border color"
+    )
+    # None of the safe tags should appear as literal escaped text
+    assert "&lt;strong&gt;" not in out, \
+        "Literal &lt;strong&gt; found — <strong> is not rendering as bold"
+    assert "&lt;/strong&gt;" not in out, \
+        "Literal &lt;/strong&gt; found — closing tag is not rendering"
+    assert "&lt;code&gt;" not in out, \
+        "Literal &lt;code&gt; found — <code> is not rendering as inline code"
+    # Each item's bold label must render correctly
+    assert "<strong>All items</strong>" in out
+    assert "<strong>Active item</strong>" in out
+    assert "<strong>Project items</strong>" in out
+    assert "<strong>Regular items</strong>" in out
+    # The code spans in items 1 and 2 must render correctly
+    assert "<code>border-radius: 0 8px 8px 0</code>" in out
+    assert "<code>#e8a030</code>" in out
+    # The surrounding prose text must be preserved
+    assert "straight left edge everywhere" in out
+    assert "same warm gold used in the logo" in out
+    assert "active always wins with gold" in out
+
+
+def test_render_md_markdown_bold_in_list_item(cleanup_test_sessions):
+    """**bold** markdown inside list items must render as <strong>."""
+    out = render_md("- **First** item\n- **Second** item with `code`")
+    assert "<strong>First</strong>" in out
+    assert "<strong>Second</strong>" in out
+    assert "<code>code</code>" in out
+
+
+def test_render_md_html_strong_in_blockquote(cleanup_test_sessions):
+    """<strong> inside blockquote must render as bold."""
+    out = render_md("> <strong>Note:</strong> pay attention")
+    assert "&lt;strong&gt;" not in out
+    assert "<strong>Note:</strong>" in out
+
+
+def test_render_md_html_strong_in_heading(cleanup_test_sessions):
+    """<strong> inside a heading must render as bold."""
+    out = render_md("## <strong>Important</strong> Section")
+    assert "&lt;strong&gt;" not in out
+    assert "<strong>Important</strong>" in out
+
+
+def test_render_md_xss_in_list_still_blocked(cleanup_test_sessions):
+    """XSS attempts in list items must still be escaped."""
+    out = render_md("- <img src=x onerror=alert(1)> bad")
+    assert "<img" not in out
+    assert "&lt;img" in out
+
+
+def test_render_md_xss_in_blockquote_still_blocked(cleanup_test_sessions):
+    """XSS in blockquote must still be escaped."""
+    out = render_md("> <script>alert(1)</script>")
+    assert "<script>" not in out
+    assert "&lt;script" in out
+
+
+def test_render_md_code_span_in_list_protected(cleanup_test_sessions):
+    """Backtick code span in list item must escape its content."""
+    out = render_md("- Use `<br>` for breaks")
+    assert "<code>&lt;br&gt;</code>" in out
+
+
+def test_render_md_code_block_protects_html(cleanup_test_sessions):
+    """HTML inside a backtick code span must NOT be converted — shown as literal."""
+    out = render_md("keep `<strong>literal</strong>` safe")
+    assert "&lt;strong&gt;" in out, "HTML inside code span should be escaped"
+    assert "<strong>literal</strong>" not in out, "HTML inside code span should NOT render as bold"
+
+
+def test_render_md_fenced_code_protects_html(cleanup_test_sessions):
+    """HTML inside a fenced code block must not be converted by the pre-pass.
+    The fenced block is stashed before tag replacement runs, so the raw HTML
+    is preserved intact for the pipeline's esc() to escape when rendering
+    the <pre><code> block. We verify the stash/restore mechanism works by
+    checking the content is unchanged after the pre-pass (i.e. still contains
+    the original tag text, not converted to **not bold**)."""
+    src = "```\n<strong>not bold</strong>\n```"
+    out = render_md(src)
+    # Pre-pass stash preserves the raw content -- it should NOT have been
+    # converted to **not bold** (which would render as bold outside the fence)
+    assert "**not bold**" not in out, \
+        "Fenced code content was incorrectly converted to markdown by the pre-pass"
+    # The raw content should still be present (stash/restore worked)
+    assert "<strong>not bold</strong>" in out or "&lt;strong&gt;" in out, \
+        "Fenced code content was lost after stash/restore"
+
+
+# ── Security: XSS must be blocked ─────────────────────────────────────────────
+
+def test_render_md_xss_img_tag_escaped(cleanup_test_sessions):
+    """<img src=x onerror=alert(1)> must be HTML-escaped, not rendered."""
+    out = render_md("<img src=x onerror=alert(1)>")
+    assert "<img" not in out, "Raw <img> tag must not appear in output"
+    assert "&lt;img" in out, "<img> must be HTML-escaped"
+
+
+def test_render_md_xss_script_tag_escaped(cleanup_test_sessions):
+    """<script>alert(1)</script> must be HTML-escaped."""
+    out = render_md("<script>alert(1)</script>")
+    assert "<script>" not in out, "Raw <script> tag must not appear in output"
+    assert "&lt;script" in out, "<script> must be HTML-escaped"
+
+
+def test_render_md_xss_iframe_escaped(cleanup_test_sessions):
+    """<iframe> must be HTML-escaped."""
+    out = render_md("<iframe src='evil.com'></iframe>")
+    assert "<iframe" not in out
+    assert "&lt;iframe" in out
+
+
+def test_render_md_xss_svg_onerror_escaped(cleanup_test_sessions):
+    """<svg onload=...> must be HTML-escaped."""
+    out = render_md("<svg onload=alert(1)>")
+    assert "<svg" not in out
+    assert "&lt;svg" in out
+
+
+def test_render_md_xss_in_bold_text_escaped(cleanup_test_sessions):
+    """**<img onerror=...>** — XSS inside markdown bold must be escaped."""
+    out = render_md("**<img src=x onerror=alert(1)>**")
+    assert "<img" not in out, "XSS inside **bold** must be escaped"
+    assert "&lt;img" in out
+
+
+def test_render_md_xss_in_html_strong_escaped(cleanup_test_sessions):
+    """<strong><img ...></strong> — nested XSS inside HTML strong must be escaped."""
+    out = render_md("<strong><img src=x onerror=alert(1)></strong>")
+    # <strong> converts to ** which then escapes the inner content via esc()
+    assert "<img" not in out, "XSS nested inside <strong> must be escaped"
+
+
+def test_render_md_xss_object_tag_escaped(cleanup_test_sessions):
+    """<object data=...> must be HTML-escaped."""
+    out = render_md("<object data='evil.swf'></object>")
+    assert "<object" not in out
+    assert "&lt;object" in out
+
+
+# ── Sprint 16 sidebar: static structure checks ───────────────────────────────
+
+# ── Exhaustive inlineMd / renderMd edge-case tests ───────────────────────────
+
+# --- Unordered list variants ---
+
+def test_list_bold_only(cleanup_test_sessions):
+    """Single bold word in list item."""
+    out = render_md("- **bold**")
+    assert "<strong>bold</strong>" in out
+    assert "&lt;" not in out
+
+def test_list_italic_only(cleanup_test_sessions):
+    """Single italic word in list item."""
+    out = render_md("- *italic*")
+    assert "<em>italic</em>" in out
+
+def test_list_code_only(cleanup_test_sessions):
+    """Single code span in list item."""
+    out = render_md("- `code`")
+    assert "<code>code</code>" in out
+
+def test_list_bold_and_code_mixed(cleanup_test_sessions):
+    """Bold and code together in one list item."""
+    out = render_md("- **run** `pip install foo`")
+    assert "<strong>run</strong>" in out
+    assert "<code>pip install foo</code>" in out
+
+def test_list_html_strong_and_code_mixed(cleanup_test_sessions):
+    """HTML <strong> and <code> together — the exact screenshot scenario."""
+    out = render_md("- <strong>Key</strong>: use <code>value</code>")
+    assert "<strong>Key</strong>" in out
+    assert "<code>value</code>" in out
+    assert "&lt;strong&gt;" not in out
+    assert "&lt;code&gt;" not in out
+
+def test_list_html_em(cleanup_test_sessions):
+    """HTML <em> in list item renders as italic."""
+    out = render_md("- <em>emphasized</em> text")
+    assert "<em>emphasized</em>" in out
+    assert "&lt;em&gt;" not in out
+
+def test_list_html_b_tag(cleanup_test_sessions):
+    """HTML <b> in list item renders as bold."""
+    out = render_md("- <b>bold via b tag</b>")
+    assert "<strong>bold via b tag</strong>" in out
+    assert "&lt;b&gt;" not in out
+
+def test_list_html_i_tag(cleanup_test_sessions):
+    """HTML <i> in list item renders as italic."""
+    out = render_md("- <i>italic via i tag</i>")
+    assert "<em>italic via i tag</em>" in out
+    assert "&lt;i&gt;" not in out
+
+def test_list_multiple_items_each_formatted(cleanup_test_sessions):
+    """Multiple list items each with different formatting."""
+    out = render_md(
+        "- **bold item**\n"
+        "- *italic item*\n"
+        "- `code item`\n"
+        "- plain item"
+    )
+    assert "<strong>bold item</strong>" in out
+    assert "<em>italic item</em>" in out
+    assert "<code>code item</code>" in out
+    assert "<li>plain item</li>" in out
+
+def test_list_item_bold_mid_sentence(cleanup_test_sessions):
+    """Bold in middle of a list item sentence."""
+    out = render_md("- Set the **timeout** to 30 seconds")
+    assert "<strong>timeout</strong>" in out
+    assert "Set the" in out
+    assert "to 30 seconds" in out
+
+def test_list_item_multiple_bold_spans(cleanup_test_sessions):
+    """Multiple bold spans in one list item."""
+    out = render_md("- **A** and **B** are both important")
+    assert "<strong>A</strong>" in out
+    assert "<strong>B</strong>" in out
+
+def test_ordered_list_bold(cleanup_test_sessions):
+    """Bold text inside ordered list items."""
+    out = render_md("1. **First** step\n2. **Second** step\n3. Plain step")
+    assert "<ol>" in out
+    assert "<strong>First</strong>" in out
+    assert "<strong>Second</strong>" in out
+    assert "<li>Plain step</li>" in out
+
+def test_ordered_list_html_strong(cleanup_test_sessions):
+    """HTML <strong> inside ordered list items renders correctly."""
+    out = render_md("1. <strong>Install</strong> the package\n2. <strong>Configure</strong> the settings")
+    assert "<ol>" in out
+    assert "<strong>Install</strong>" in out
+    assert "<strong>Configure</strong>" in out
+    assert "&lt;strong&gt;" not in out
+
+def test_ordered_list_code_spans(cleanup_test_sessions):
+    """Code spans inside ordered list items."""
+    out = render_md("1. Run `npm install`\n2. Run `npm start`")
+    assert "<code>npm install</code>" in out
+    assert "<code>npm start</code>" in out
+
+def test_indented_list_item_bold(cleanup_test_sessions):
+    """Bold inside indented (nested) list item."""
+    out = render_md("- top level\n  - **nested bold**")
+    assert "<strong>nested bold</strong>" in out
+    assert "margin-left:16px" in out
+
+# --- Blockquote variants ---
+
+def test_blockquote_plain(cleanup_test_sessions):
+    """Plain blockquote wraps in <blockquote>."""
+    out = render_md("> simple quote")
+    assert "<blockquote>simple quote</blockquote>" in out
+
+def test_blockquote_bold(cleanup_test_sessions):
+    """**bold** inside blockquote renders correctly."""
+    out = render_md("> **important** note")
+    assert "<strong>important</strong>" in out
+
+def test_blockquote_html_strong(cleanup_test_sessions):
+    """<strong> inside blockquote renders as bold."""
+    out = render_md("> <strong>Warning:</strong> read this")
+    assert "<strong>Warning:</strong>" in out
+    assert "&lt;strong&gt;" not in out
+
+def test_blockquote_code_span(cleanup_test_sessions):
+    """Code span inside blockquote renders correctly."""
+    out = render_md("> Use `git commit` to save")
+    assert "<code>git commit</code>" in out
+
+def test_blockquote_mixed_formatting(cleanup_test_sessions):
+    """Mixed bold and code in blockquote."""
+    out = render_md("> **Note:** run `pip install foo` first")
+    assert "<strong>Note:</strong>" in out
+    assert "<code>pip install foo</code>" in out
+
+def test_blockquote_xss_blocked(cleanup_test_sessions):
+    """XSS in blockquote content must be escaped."""
+    out = render_md("> <img src=x onerror=alert(1)>")
+    assert "&lt;img" in out
+    assert "<img" not in out
+
+# --- Heading variants ---
+
+def test_heading_h1_bold(cleanup_test_sessions):
+    """Bold inside h1 renders correctly."""
+    out = render_md("# **Main** Title")
+    assert "<h1><strong>Main</strong> Title</h1>" in out
+
+def test_heading_h2_html_strong(cleanup_test_sessions):
+    """HTML <strong> inside h2 renders correctly."""
+    out = render_md("## <strong>Section</strong> Name")
+    assert "<h2><strong>Section</strong> Name</h2>" in out
+    assert "&lt;strong&gt;" not in out
+
+def test_heading_h3_code(cleanup_test_sessions):
+    """Code span inside h3 renders correctly."""
+    out = render_md("### The `renderMd` function")
+    assert "<h3>The <code>renderMd</code> function</h3>" in out
+
+def test_heading_xss_blocked(cleanup_test_sessions):
+    """XSS attempt in heading must be escaped."""
+    out = render_md("## <script>alert(1)</script>")
+    assert "<script>" not in out
+    assert "&lt;script" in out
+
+# --- Paragraph / top-level formatting ---
+
+def test_paragraph_bold_renders(cleanup_test_sessions):
+    """Bold in a plain paragraph renders correctly."""
+    out = render_md("The **quick brown fox** jumps.")
+    assert "<strong>quick brown fox</strong>" in out
+
+def test_paragraph_html_strong_renders(cleanup_test_sessions):
+    """HTML <strong> in a plain paragraph renders correctly."""
+    out = render_md("The <strong>quick brown fox</strong> jumps.")
+    assert "<strong>quick brown fox</strong>" in out
+    assert "&lt;strong&gt;" not in out
+
+def test_paragraph_html_code_renders(cleanup_test_sessions):
+    """HTML <code> in a plain paragraph renders correctly."""
+    out = render_md("Call <code>foo()</code> to start.")
+    assert "<code>foo()</code>" in out
+    assert "&lt;code&gt;" not in out
+
+def test_paragraph_br_creates_line_break(cleanup_test_sessions):
+    """<br> in paragraph becomes a line break inside <p>."""
+    out = render_md("Line one<br>Line two")
+    # br converts to \n which inside <p> becomes <br>
+    assert "Line one" in out and "Line two" in out
+
+def test_multiple_paragraphs_separated(cleanup_test_sessions):
+    """Double newline creates separate <p> elements."""
+    out = render_md("First paragraph.\n\nSecond paragraph.")
+    assert out.count("<p>") == 2
+
+# --- Table variants ---
+
+def test_table_structure_in_ui_js(cleanup_test_sessions):
+    """ui.js must contain table rendering logic with thead/tbody structure."""
+    src = (REPO_ROOT / "static" / "ui.js").read_text()
+    assert "<table>" in src or "table>" in src, "table rendering not found in ui.js"
+    assert "thead" in src, "thead not found in table renderer"
+    assert "tbody" in src, "tbody not found in table renderer"
+    assert "parseRow" in src, "parseRow helper not found in table renderer"
+
+# --- br tag specifically ---
+
+def test_br_in_list_item(cleanup_test_sessions):
+    """<br> inside a list item becomes a newline."""
+    out = render_md("- Line one<br>Line two")
+    assert "Line one" in out
+    assert "Line two" in out
+
+def test_br_self_closing_in_paragraph(cleanup_test_sessions):
+    """<br/> self-closing form is also handled."""
+    out = render_md("Before<br/>After")
+    assert "Before" in out and "After" in out
+
+# --- No double-escaping ---
+
+def test_no_double_escaping_ampersand(cleanup_test_sessions):
+    """A literal & in text must become &amp; exactly once, not &amp;amp;."""
+    out = render_md("foo & bar")
+    assert "&amp;amp;" not in out
+    assert "&amp;" in out or "foo & bar" in out  # either fine (paragraph wrap may not escape)
+
+def test_no_double_escaping_lt_in_code(cleanup_test_sessions):
+    """< inside a code span must become &lt; exactly once."""
+    out = render_md("`a < b`")
+    assert "&lt;lt;" not in out
+    assert "&lt;" in out
+
+def test_strong_text_not_double_escaped(cleanup_test_sessions):
+    """Content of <strong> must not be double-escaped."""
+    out = render_md("<strong>hello & world</strong>")
+    # The & inside strong content should be escaped once
+    assert "&amp;amp;" not in out
+    assert "<strong>" in out
+
+# --- inlineMd helper present in source ---
+
+def test_inline_md_helper_in_ui_js(cleanup_test_sessions):
+    """ui.js must define inlineMd() helper function."""
+    src = (REPO_ROOT / "static" / "ui.js").read_text()
+    assert "function inlineMd(" in src, "inlineMd() helper not found in ui.js"
+
+def test_inline_md_used_in_list_handler(cleanup_test_sessions):
+    """List handler in ui.js must call inlineMd() not esc() for item text."""
+    src = (REPO_ROOT / "static" / "ui.js").read_text()
+    # Find the list block handler
+    ul_idx = src.find("html+='<ul>'") or src.find('html+=`<ul>`') or src.find("let html='<ul>'")
+    assert ul_idx >= 0 or "inlineMd(text)" in src, "inlineMd not called in list handler"
+    # Verify inlineMd is called, not bare esc
+    assert "inlineMd(text)" in src, "inlineMd(text) call not found — list items may not render formatting"
+
+def test_inline_md_used_in_blockquote_handler(cleanup_test_sessions):
+    """Blockquote handler in ui.js must call inlineMd() not esc() for content."""
+    src = (REPO_ROOT / "static" / "ui.js").read_text()
+    assert "inlineMd(t)" in src, "inlineMd not called in blockquote/heading handler"
+
+
+def test_sessions_js_has_svg_icons(cleanup_test_sessions):
+    """sessions.js must define ICONS object with SVG strings for sidebar buttons."""
+    src = REPO_ROOT / "static" / "sessions.js"
+    code = src.read_text()
+    assert "const ICONS=" in code or "const ICONS =" in code, "ICONS constant not found"
+    for icon in ["pin", "folder", "archive", "trash", "dup"]:
+        assert icon + ":" in code or f"'{icon}'" in code, f"ICONS.{icon} not found"
+    assert "<svg" in code, "SVG content not found in ICONS"
+
+
+def test_sessions_js_has_overlay_actions(cleanup_test_sessions):
+    """sessions.js must use .session-actions overlay div for action buttons."""
+    src = REPO_ROOT / "static" / "sessions.js"
+    code = src.read_text()
+    assert "session-actions" in code, ".session-actions overlay not found in sessions.js"
+
+
+def test_style_css_has_session_actions_overlay(cleanup_test_sessions):
+    """style.css must define .session-actions with position:absolute."""
+    src = REPO_ROOT / "static" / "style.css"
+    code = src.read_text()
+    assert ".session-actions" in code, ".session-actions not found in style.css"
+    assert "position:absolute" in code or "position: absolute" in code, \
+        ".session-actions must use position:absolute for overlay"
+
+
+def test_style_css_active_session_uses_gold(cleanup_test_sessions):
+    """Active session style should use gold/amber color (#e8a030) not just blue."""
+    src = REPO_ROOT / "static" / "style.css"
+    code = src.read_text()
+    assert "#e8a030" in code, \
+        "Active session gold color (#e8a030) not found in style.css"
+
+
+def test_sessions_js_active_skips_project_border(cleanup_test_sessions):
+    """sessions.js must not override active session border-left with project color."""
+    src = REPO_ROOT / "static" / "sessions.js"
+    code = src.read_text()
+    # The fix: only set borderLeftColor if NOT the active session
+    assert "isActive" in code, "isActive check not found in sessions.js"
+    assert "borderLeftColor" in code, "borderLeftColor not found in sessions.js"