feat(x): native application menu bar

[hrsvrn]

What

Replaces Electron's factory-default menu (electronjs.org Help links, DevTools and Reload enabled in production) with a full native application menu for the desktop app.

• File — New Chat (⌘N), New Note (⇧⌘N), Export Note (md / pdf / docx)
• Edit — undo/redo + clipboard. On Windows/Linux undo/redo route through the renderer so the markdown editor's history routing keeps working; macOS keeps the standard roles, identical to the old default menu
• View — Search (⌘K), Toggle Sidebar (⌘), Full-Screen Chat (⌘L), zoom controls, full screen; Reload / Force Reload / DevTools are now dev-only
• Go — Back/Forward plus all ten sections (Home, Email, Meetings, Brain, Apps, Code, Live Notes, Chat History, Background Tasks, Graph) with ⌘1–9
• Tools — Quick Ask (shows the live global chord, hidden when unregistered), Start/Stop Meeting Notes with dynamic relabel (same hook as the tray)
• Help — GitHub / Report an Issue / Release Notes, Keyboard Shortcuts (deep-links the settings tab), Open Data Folder (~/.rowboat), About, and a state-aware "Check for Updates…" that becomes "Restart to Update" when an update is staged, and links to GitHub releases on Linux where autoUpdater is unsupported

How

• New apps/main/src/menu.ts, installed before the window is created so Linux/Windows never paint the default menu. Rebuilt on recording-state changes, quick-ask rebinds, and updater transitions — mirrors tray.ts.
• Two new typed IPC channels: menu:command (one discriminated payload; each command reuses the exact code path of the in-app control it mirrors) and menu:toggleSidebar (its own channel because the handler must live under the SidebarProvider). Go-menu navigation needs no channel — it rides the existing deep-link pipeline (dispatchDeepLink → app:openUrl), which already parks URLs while the renderer loads.
• Zoom logic extracted from main.ts into zoom.ts so menu clicks and the before-input-event keystroke handler share one implementation; the stale "Linux suppresses the menu bar" comment is corrected in the move.
• Chords the renderer already handles (⌘K/⌘N/⌘L/⌘Z) are display-only in the menu on Windows/Linux (registerAccelerator: false), so existing keyboard behavior is untouched.
• updater.ts gains onUpdaterStatusChanged; menu-opened Settings gets its own dialog instance that can deep-link any tab (ConfigTab is now exported).

Testing

• npm run deps, npm run lint, npm run typecheck all pass; apps/main additionally typechecked directly with tsc --noEmit (it is not covered by the workspace typecheck script).
• 75-second dev-app boot on Linux: no main-process errors, menu renders with all sections.
• Linux menu bar stays always-visible; flipping to Alt-to-reveal is a one-line autoHideMenuBar change if preferred.