Add a global command palette (⌘K / Ctrl+K)

[DragonnZhang]

Closes #41

What & why

Every comparable desktop app ships a command palette — a keyboard-driven
overlay to search for and run any command (⌘K in Claude Code Desktop / Linear,
⌘⇧P in VS Code / Codex desktop). OpenWork already had all the pieces — a
centralized action registry with an execute(actionId) method, the cmdk
command primitives, and translated action labels — but they were only
surfaced in read-only reference views (the Keyboard Shortcuts dialog and the
Settings → Shortcuts page). There was no way to run an action by searching for
it.

This adds a global command palette opened with ⌘K / Ctrl+K (and from the app
menu). It:

• lists every registry action, grouped by category, with its hotkey on the right,
• filters as you type (cmdk's built-in fuzzy match over the translated label),
• shows a “No results found” empty state,
• on select, closes and calls the registry's execute() — so the action runs
  exactly as if its hotkey were pressed,
• closes on Esc / selection, integrated with the existing modal stack.

Frontend-only. No backend / qwen-code change. No new i18n keys — the input
placeholder reuses commands.searchCommands, the empty state reuses
common.noResultsFound, labels reuse shortcuts.action.*, and group headings
reuse shortcuts.category.*.

Changes

• actions/definitions.ts — new app.commandPalette action (mod+k).
• components/CommandPalette.tsx — the palette. Self-contained: it registers
  its own open handler, owns its open state, and joins the modal stack for
  layered close. Mounted once in App.tsx (inside the action + modal providers).
• actions/action-i18n.ts — extracted the action-ID → i18n-key map
  (ACTION_LABEL_KEYS) plus a category-key helper into a shared module, and reuse
  it from Settings → Shortcuts (pages/settings/ShortcutsPage.tsx) so the two
  surfaces can't drift.
• components/AppMenu.tsx — a “Command Palette” entry for discoverability.
• e2e/assertions/command-palette.assert.ts — new CDP assertion (below).
• e2e/app.ts — give each launched app instance its own profile dir keyed on
  the unique debug port. Electron's single-instance lock is keyed on userData, so
  a shared dir made a second assertion's launch defer to the first instance and
  never get its own renderer target. Per-port dirs let multiple assertions run in
  one bun run e2e.

Verification (DoD)

• Feature CDP assertion — ✅, and the full e2e suite is green (2/2):

🧪 Running 2 e2e assertion(s)
  • app boots and main window renders ... ✅ (3764ms)
  • command palette opens, filters, and runs an action ... ✅ (3639ms)
✅ 2/2 passed

The command-palette assertion drives the real built app over CDP through the
whole path: presses Ctrl/Cmd+K and asserts the palette opens with more than one
action row; types theme and asserts the list narrows (every visible row
contains the query, count shrinks) with Toggle Theme surviving; types a
no-match query and asserts the empty state with zero rows; clears and asserts
the full list is restored; then selects Toggle Theme and asserts the palette
closes and the app theme actually flips (documentElement dark⇄light) —
proving the palette executes the action, not merely displays it.

• bun run typecheck:all — introduces no new errors. packages/{core, shared, server-core, server, session-tools-core, ui} all pass; the only errors
  are 11 pre-existing ones in apps/electron unrelated to this change
  (auto-update.ts, a settings-default-thinking test tuple, and two test files
  importing vitest, which is in no package.json). None are in the files this PR
  touches.
• bun test — the failing set is byte-for-byte identical to main
  (56 pre-existing failures: BrowserCDP, BrowserPaneManager, i18n locale-parity
  sorted checks, startWebuiHttpServer, resource-bundle, etc.). This change
  adds zero new failures.
• Electron build — ✅. App boots — ✅ (app boots assertion).

Part of the autonomous desktop-feature loop (loop-bot).

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Generated by Claude Code

[DragonnZhang]

@copilot resolve the merge conflicts in this pull request

[DragonnZhang]

@copilot resolve the merge conflicts in this pull request