fix(review): wire Session Manager to /api/sessions/unified contract, stop Ctrl+K PTY leak, finish shortcut registry (PR #146)

- Session Manager (COD-121/192): align _loadSessionManagerList() with the
  merged #139 endpoint — map UnifiedSessionItem fields (lastActivityAt
  epoch-ms → lastModified, optional sizeBytes/firstPrompt/name) to the
  history-record shape _buildHistoryItem renders; surface non-2xx /
  error-envelope responses as a visible message instead of a silent
  "No sessions found"; route clicks by liveness (live row → selectSession,
  history row → resumeHistorySession by conversation UUID) via a new
  onActivate option so a live session is never duplicate-resumed
- Ctrl+K double-dispatch: gate the palette chord in
  attachCustomKeyEventHandler (return false on keydown) so xterm never
  writes 0x0b kill-line into the PTY while the palette opens; gate is
  registry-aware so a rebound/disabled palette shortcut restores normal
  terminal Ctrl+K
- Shortcut registry (COD-157) finished per maintainer decision: document
  keydown now dispatches through getShortcutRegistry() +
  matchesShortcutEvent() (legacy SHORTCUTS table removed), honoring
  per-shortcut disable and rebinds incl. the palette chord; overrides
  persist via saveAppSettingsToStorage() (correct device key + cache
  coherence, was orphaned 'codeman:settings'); Shortcuts tab renders on
  open via switchSettingsTab hook; capture uses a persistent listener that
  ignores bare modifier keydowns (combos now capturable) and requires a
  Ctrl/Cmd/Alt chord; settings rows use delegated listeners instead of
  inline onclick (JS-string injection sink) and overrides can no longer
  clobber id/label/action; added the missing row + overlay CSS
- matchesShortcutEvent: reject undeclared extra modifiers (Ctrl+Shift+K
  no longer hijacked from Firefox devtools) while keeping Ctrl/Cmd
  interchangeable; match physical code OR produced key for layout parity
- Registry/dispatch gaps: added restore-terminal-size entry, documented
  Ctrl+Shift+R again in the help modal (test flipped to assert presence),
  Ctrl+?/Alt+? now really open the registry-driven shortcut overlay, and
  Escape closes it
- Palette new-session pick routes through selectQuickStartCase() so the
  searchable combobox, dir display, and lastUsedCase stay in sync
- Removed fork cherry-pick debris: dead _onSessionListMaybeChanged(),
  orphaned .session-row-menu CSS, nonexistent closeMobileHeaderUtilities
  calls
- Tests: functional vm-harness coverage for the unified-list field
  mapping + error state + liveness routing, palette chord shift/disable/
  rebind handling, override persistence round-trip, capture flow, tab
  render hook, and source guards for the PTY gate + registry dispatch

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/web/public/index.html

@@ -597,6 +597,7 @@
               <div><kbd>Ctrl</kbd>+<kbd>L</kbd></div><div>Clear Terminal</div>
               <div><kbd>Ctrl</kbd>+<kbd>+</kbd></div><div>Increase Font</div>
               <div><kbd>Ctrl</kbd>+<kbd>-</kbd></div><div>Decrease Font</div>
+              <div><kbd>Ctrl</kbd>+<kbd>Shift</kbd>+<kbd>R</kbd></div><div>Restore Terminal Size</div>
               <div><kbd>Shift</kbd>+<kbd>Enter</kbd></div><div>Insert Newline</div>
               <div><kbd>Ctrl</kbd>+<kbd>Enter</kbd></div><div>Insert Newline</div>
               <div><kbd>Ctrl</kbd>+<kbd>Shift</kbd>+<kbd>V</kbd></div><div>Voice Input</div>