Hermes Web UI — Sprints 11-14: multi-provider models, settings, session QoL, alerts, polish

Sprint 11 (v0.13): multi-provider model support, streaming smoothness
- Dynamic model dropdown populated from configured API keys (OpenAI, Anthropic,
  Google, DeepSeek, GLM, Kimi, MiniMax, OpenRouter, Nous Portal)
- Scroll pinning during streaming (no forced scroll when user has scrolled up)
- All route handlers extracted to api/routes.py (server.py now ~76 lines)

Sprint 12 (v0.14): settings panel, SSE reconnect, session QoL
- Settings panel (gear icon) -- persist default model and workspace server-side
- SSE auto-reconnect on network blips
- Pin/star sessions to top of sidebar
- Import session from JSON export

Sprint 13 (v0.15): cron alerts, background errors, session duplicate, tab title
- Cron completion alerts: toast per completion + unread badge on Tasks tab
- Background agent error banner when a non-active session errors mid-stream
- Session duplicate button
- Browser tab title reflects active session name

Sprint 14 (v0.16): Mermaid diagrams, file ops, session archive/tags, timestamps
- Mermaid diagram rendering inline (dark theme, lazy CDN load)
- File rename (double-click in file tree) and create folder
- Session archive (hide without deleting, toggle to show)
- Session tags -- #hashtag in title becomes colored chip + click-to-filter
- Message timestamps (HH:MM on hover, full date as tooltip)

Test suite: 224 tests across 14 sprint files + regression gate, 0 failures.

api/models.py

@@ -1,5 +1,5 @@
 """
-Hermes WebUI -- Session model and in-memory session store.
+Hermes Web UI -- Session model and in-memory session store.
 """
 import collections
 import json
@@ -7,6 +7,7 @@ import time
 import uuid
 from pathlib import Path
 
+import api.config as _cfg
 from api.config import (
     SESSION_DIR, SESSION_INDEX_FILE, SESSIONS, SESSIONS_MAX,
     LOCK, DEFAULT_WORKSPACE, DEFAULT_MODEL
@@ -33,8 +34,8 @@ def _write_session_index():
 
 
 class Session:
-    def __init__(self, session_id=None, title='Untitled', workspace=str(DEFAULT_WORKSPACE), model=DEFAULT_MODEL, messages=None, created_at=None, updated_at=None, tool_calls=None, **kwargs):
-        self.session_id = session_id or uuid.uuid4().hex[:12]; self.title = title; self.workspace = str(Path(workspace).expanduser().resolve()); self.model = model; self.messages = messages or []; self.tool_calls = tool_calls or []; self.created_at = created_at or time.time(); self.updated_at = updated_at or time.time()
+    def __init__(self, session_id=None, title='Untitled', workspace=str(DEFAULT_WORKSPACE), model=DEFAULT_MODEL, messages=None, created_at=None, updated_at=None, tool_calls=None, pinned=False, archived=False, **kwargs):
+        self.session_id = session_id or uuid.uuid4().hex[:12]; self.title = title; self.workspace = str(Path(workspace).expanduser().resolve()); self.model = model; self.messages = messages or []; self.tool_calls = tool_calls or []; self.created_at = created_at or time.time(); self.updated_at = updated_at or time.time(); self.pinned = bool(pinned); self.archived = bool(archived)
     @property
     def path(self): return SESSION_DIR / f'{self.session_id}.json'
     def save(self): self.updated_at = time.time(); self.path.write_text(json.dumps(self.__dict__, ensure_ascii=False, indent=2), encoding='utf-8'); _write_session_index()
@@ -43,7 +44,7 @@ class Session:
         p = SESSION_DIR / f'{sid}.json'
         if not p.exists(): return None
         return cls(**json.loads(p.read_text(encoding='utf-8')))
-    def compact(self): return {'session_id': self.session_id, 'title': self.title, 'workspace': self.workspace, 'model': self.model, 'message_count': len(self.messages), 'created_at': self.created_at, 'updated_at': self.updated_at}
+    def compact(self): return {'session_id': self.session_id, 'title': self.title, 'workspace': self.workspace, 'model': self.model, 'message_count': len(self.messages), 'created_at': self.created_at, 'updated_at': self.updated_at, 'pinned': self.pinned, 'archived': self.archived}
 
 def get_session(sid):
     with LOCK:
@@ -61,7 +62,8 @@ def get_session(sid):
     raise KeyError(sid)
 
 def new_session(workspace=None, model=None):
-    s = Session(workspace=workspace or get_last_workspace(), model=model or DEFAULT_MODEL)
+    # Use _cfg.DEFAULT_MODEL (not the import-time snapshot) so save_settings() changes take effect
+    s = Session(workspace=workspace or get_last_workspace(), model=model or _cfg.DEFAULT_MODEL)
     with LOCK:
         SESSIONS[s.session_id] = s
         SESSIONS.move_to_end(s.session_id)
@@ -80,7 +82,7 @@ def all_sessions():
             with LOCK:
                 for s in SESSIONS.values():
                     index_map[s.session_id] = s.compact()
-            result = sorted(index_map.values(), key=lambda s: s['updated_at'], reverse=True)
+            result = sorted(index_map.values(), key=lambda s: (s.get('pinned', False), s['updated_at']), reverse=True)
             # Hide empty Untitled sessions from the UI (created by tests, page refreshes, etc.)
             result = [s for s in result if not (s.get('title','Untitled')=='Untitled' and s.get('message_count',0)==0)]
             return result
@@ -97,7 +99,7 @@ def all_sessions():
             pass
     for s in SESSIONS.values():
         if all(s.session_id != x.session_id for x in out): out.append(s)
-    out.sort(key=lambda s: s.updated_at, reverse=True)
+    out.sort(key=lambda s: (getattr(s, 'pinned', False), s.updated_at), reverse=True)
     return [s.compact() for s in out if not (s.title=='Untitled' and len(s.messages)==0)]