feat(terminal): refactor runtime and add mobile workspace (#2280)

Replace the legacy terminal flow with a shared authenticated WebSocket
runtime used across web, desktop, relay, and mobile surfaces.

- introduce the v3 terminal protocol with scoped attachments, snapshots,
  ordered output, bounded replay history, reconnects, and explicit lifecycle
- harden PTY creation, restart, resize, close, force-kill, idle cleanup,
  shell selection, login mode, environment sanitization, and appearance sync
- add runtime-aware terminal APIs with relay authentication and Electron parity
- add a fullscreen mobile terminal workspace with touch scrolling,
  long-press selection, safe-area controls, quick keys, and Ctrl/Alt input
- add terminal selection attachments, preview detection, project actions,
  shell settings, and localized UI
- harden Ghostty rendering, resize recovery, Unicode handling, block
  characters, line height, and stale-row behavior
- remove the obsolete terminal SSE path and update reverse-proxy guidance
- expand terminal runtime, transport, input, selection, and store coverage
- avoid duplicate web builds when preparing mobile assets in root CI builds

packages/ui/src/lib/desktop.ts

@@ -1,4 +1,4 @@
-import type { ProjectEntry } from '@/lib/api/types';
+import type { ProjectEntry, TerminalShell } from '@/lib/api/types';
 import { getInjectedBootOutcome } from '@/lib/desktopBoot';
 import type { DraftStarterRef } from '@/lib/draftStarters';
 import type { MobileKeyboardMode } from '@/lib/mobileKeyboardMode';
@@ -163,6 +163,8 @@ export type DesktopSettings = {
   showSplitAssistantMessageActions?: boolean;
   fontSize?: number;
   terminalFontSize?: number;
+  terminalShell?: TerminalShell;
+  terminalLoginShells?: TerminalShell[];
   editorFontSize?: number;
   uiFont?: string;
   monoFont?: string;