feat: Sprint 21 — mobile responsive layout + Docker support

Mobile responsive (Issue #21):
- Hamburger sidebar: slide-in overlay on mobile (<640px) with backdrop.
  Tap hamburger in topbar to open, tap outside to close. Full session
  list, project chips, all panel content accessible.
- Bottom navigation bar: 5-tab fixed bar (Chat, Tasks, Skills, Memory,
  Spaces) replaces sidebar nav tabs on mobile. iOS-style layout.
  Tapping a tab opens the sidebar overlay with that panel active.
- Right panel slide-over: Files button in topbar chips opens workspace
  panel as a slide-over from the right on mobile/tablet.
- Touch targets: all interactive elements get min 44x44px touch areas.
  Session items, approval buttons, composer buttons all sized for fingers.
- Composer positioned above bottom nav bar with proper spacing.
- Sidebar nav tabs and bottom section hidden on mobile (replaced by
  bottom nav + topbar chips).
- Clicking a session auto-closes the sidebar overlay.
- Desktop layout completely unchanged — all mobile elements are
  display:none by default, only shown inside @media(max-width:640px).

Docker (Issue #7):
- Dockerfile: python:3.12-slim, HERMES_WEBUI_HOST=0.0.0.0, port 8787.
- docker-compose.yml: named volume for state persistence, optional
  ~/.hermes mount for agent features, password env var documented.
- README: Docker quick start section with compose and manual commands.

Tests: 392 passed, 23 pre-existing failures, 0 regressions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

static/index.html

@@ -143,6 +143,9 @@
   </aside>
   <main class="main">
     <div class="topbar">
+      <button class="mobile-hamburger" id="btnHamburger" onclick="toggleMobileSidebar()" title="Menu">
+        <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><line x1="3" y1="6" x2="21" y2="6"/><line x1="3" y1="12" x2="21" y2="12"/><line x1="3" y1="18" x2="21" y2="18"/></svg>
+      </button>
       <div style="flex:1;min-width:0;overflow:hidden"><div class="topbar-title" id="topbarTitle">Hermes</div><div class="topbar-meta" id="topbarMeta">Start a new conversation</div></div>
       <div class="topbar-chips">
         <div class="chip model" id="modelChip">GPT-5.4 Mini</div>
@@ -152,6 +155,7 @@
         </div>
         <button class="chip clear-btn" id="btnClearConv" onclick="clearConversation()" title="Clear all messages in this conversation" style="display:none">&#128465; Clear</button>
         <button class="chip gear-btn" id="btnSettings" onclick="toggleSettings()" title="Settings">&#9881;</button>
+        <button class="chip mobile-files-btn" id="btnMobileFiles" onclick="toggleMobileFiles()" title="Files">&#128193;</button>
       </div>
     </div>
     <div class="messages" id="messages">
@@ -301,6 +305,29 @@
     </div>
   </div>
 </div>
+<div class="mobile-overlay" id="mobileOverlay" onclick="closeMobileSidebar()"></div>
+<nav class="mobile-bottom-nav" id="mobileBottomNav">
+  <button class="mobile-nav-btn active" data-panel="chat" onclick="mobileSwitchPanel('chat')">
+    <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5"><path d="M21 15a2 2 0 0 1-2 2H7l-4 4V5a2 2 0 0 1 2-2h14a2 2 0 0 1 2 2z"/></svg>
+    <span>Chat</span>
+  </button>
+  <button class="mobile-nav-btn" data-panel="tasks" onclick="mobileSwitchPanel('tasks')">
+    <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5"><rect x="3" y="4" width="18" height="18" rx="2"/><line x1="16" y1="2" x2="16" y2="6"/><line x1="8" y1="2" x2="8" y2="6"/><line x1="3" y1="10" x2="21" y2="10"/></svg>
+    <span>Tasks</span>
+  </button>
+  <button class="mobile-nav-btn" data-panel="skills" onclick="mobileSwitchPanel('skills')">
+    <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5"><path d="M12 2L2 7l10 5 10-5-10-5z"/><path d="M2 17l10 5 10-5"/><path d="M2 12l10 5 10-5"/></svg>
+    <span>Skills</span>
+  </button>
+  <button class="mobile-nav-btn" data-panel="memory" onclick="mobileSwitchPanel('memory')">
+    <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5"><path d="M12 2a7 7 0 0 1 7 7c0 2.5-1.3 4.7-3.2 6H8.2C6.3 13.7 5 11.5 5 9a7 7 0 0 1 7-7z"/><line x1="9" y1="17" x2="15" y2="17"/><line x1="10" y1="20" x2="14" y2="20"/></svg>
+    <span>Memory</span>
+  </button>
+  <button class="mobile-nav-btn" data-panel="workspaces" onclick="mobileSwitchPanel('workspaces')">
+    <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5"><path d="M2 4h8l2 2h10v14H2z"/></svg>
+    <span>Spaces</span>
+  </button>
+</nav>
 <div class="toast" id="toast"></div>
 <script src="/static/ui.js"></script>
 <script src="/static/workspace.js"></script>