Agentic UI: Keyboard Shortcuts and Settings

[shaunandrews]

Related issues

• None.

How AI was used in this PR

AI helped split the keyboard shortcut work out of the larger interface-improvements branch, keeping the branch focused and rerunning the relevant checks.

Proposed Changes

• Adds classic UI keyboard shortcut handling and a settings surface for configuring how chat messages are sent.
• Keeps shortcut-specific preferences, IPC wiring, menu actions, and shortcut labels in a focused stacked PR instead of the base interface work.

Testing Instructions

• npm run typecheck
• npm test -- apps/ui/src/lib/keyboard-shortcuts.test.ts apps/studio/src/tests/menu.test.ts apps/ui/src/components/settings-view/index.test.tsx apps/ui/src/components/site-preview/index.test.tsx apps/ui/src/ui-desks/widgets/site-shortcuts/component/index.test.tsx

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[shaunandrews]

Code review findings (via Claude Code) that apply to this branch:

1. Cmd+N does nothing on the Desks UI (the default mode)
CommandOrControl+N was removed from the "Add Site" menu item and reassigned to the new-chat-in-current-site shortcut, but the handler for that shortcut is only registered in ui-classic's session view. On ui-desks — currently the default mode — Cmd+N silently does nothing. Either register a desks handler or keep a menu accelerator as fallback.

2. Duplicate subscriptions to toggle-site-preview
Both apps/ui/src/hooks/use-session-ui.tsx (~L119) and apps/ui/src/ui-classic/router/layout-dashboard/index.tsx (~L98) subscribe to the same IPC event. The provider has a nesting guard, but the layout-dashboard subscription lives outside it — if both end up mounted and active, one menu click toggles twice (net no-op). Worth consolidating into a single owner.

3. isApplePlatform duplicates isMacPlatform
apps/ui/src/lib/keyboard-shortcuts.ts adds isApplePlatform() while apps/ui/src/lib/platform.ts already has isMacPlatform(), with slightly different regexes. These should be one function so platform detection can't drift. (The third copy in inspector-script.ts is fine — it's serialized into the guest page and can't import.)

4. window.confirm() for destructive preview-site deletion
settings-view/index.tsx uses native window.confirm() to confirm deleting a preview site. The app already has a styled Dialog pattern for destructive actions (e.g. DeleteSiteDialog in site-list); native confirm breaks the visual language and can behave inconsistently in Electron renderers.

5. Saved-defaults resolution duplicated in settings form logic
In settings-view/index.tsx, toFormData and diffFromSaved each independently resolve saved defaults (defaultSiteDirectory ?? '', messageSendShortcut ?? DEFAULT_MESSAGE_SEND_SHORTCUT, studioCliInstalled ?? false). Changing a default requires updating both in sync — worth extracting a single resolver.

Things checked that look good: i18n coverage in the new settings view is complete, ⌘/Ctrl shortcut display handles Windows/Linux correctly with test coverage, and the settings CSS consistently uses design tokens.