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/boot.js

@@ -8,6 +8,43 @@ async function cancelStream(){
   }catch(e){setStatus('Cancel failed: '+e.message);}
 }
 
+// ── Mobile navigation ──────────────────────────────────────────────────────
+function toggleMobileSidebar(){
+  const sidebar=document.querySelector('.sidebar');
+  const overlay=$('mobileOverlay');
+  if(!sidebar)return;
+  const isOpen=sidebar.classList.contains('mobile-open');
+  if(isOpen){closeMobileSidebar();}
+  else{sidebar.classList.add('mobile-open');if(overlay)overlay.classList.add('visible');}
+}
+function closeMobileSidebar(){
+  const sidebar=document.querySelector('.sidebar');
+  const overlay=$('mobileOverlay');
+  if(sidebar)sidebar.classList.remove('mobile-open');
+  if(overlay)overlay.classList.remove('visible');
+}
+function toggleMobileFiles(){
+  const panel=document.querySelector('.rightpanel');
+  if(!panel)return;
+  panel.classList.toggle('mobile-open');
+}
+function mobileSwitchPanel(name){
+  // Close sidebar if open, then switch panel
+  closeMobileSidebar();
+  // Open sidebar for the selected panel, then close after a moment
+  const sidebar=document.querySelector('.sidebar');
+  const overlay=$('mobileOverlay');
+  if(sidebar){
+    sidebar.classList.add('mobile-open');
+    if(overlay)overlay.classList.add('visible');
+  }
+  switchPanel(name);
+  // Update bottom nav active state
+  document.querySelectorAll('.mobile-nav-btn').forEach(btn=>{
+    btn.classList.toggle('active',btn.dataset.panel===name);
+  });
+}
+
 $('btnSend').onclick=()=>{if(window._micActive)_stopMic();send();};
 $('btnAttach').onclick=()=>$('fileInput').click();