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/components/layout/Header.tsx

@@ -64,7 +64,6 @@ import type { GitHubAuthStatus } from '@/lib/api/types';
 import type { SessionContextUsage } from '@/stores/types/sessionTypes';
 import { DesktopHostSwitcherDialog } from '@/components/desktop/DesktopHostSwitcher';
 import { OpenInAppButton } from '@/components/desktop/OpenInAppButton';
-import { forceKillTerminal } from '@/lib/terminalApi';
 import { useTerminalStore } from '@/stores/useTerminalStore';
 import { ProjectActionsButton } from '@/components/layout/ProjectActionsButton';
 import { SessionSwitcherDropdown } from '@/components/session/SessionSwitcherDropdown';
@@ -1776,7 +1775,8 @@ export const Header: React.FC<HeaderProps> = ({
   }, [shortcutOverrides]);
 
   useEffect(() => {
-    if (!isMobile && (activeMainTab === 'git' || activeMainTab === 'terminal' || activeMainTab === 'diff' || activeMainTab === 'files' || activeMainTab === 'context')) {
+    // Project actions may intentionally promote the terminal to the desktop main view.
+    if (!isMobile && (activeMainTab === 'git' || activeMainTab === 'diff' || activeMainTab === 'files' || activeMainTab === 'context')) {
       setActiveMainTab('chat');
     }
   }, [activeMainTab, isMobile, setActiveMainTab]);
@@ -1831,7 +1831,7 @@ export const Header: React.FC<HeaderProps> = ({
 
       try {
         // Ensure preview/dev terminals don't linger.
-        await forceKillTerminal({});
+        await runtimeApis.terminal.forceKill?.({});
       } catch {
         // ignore
       }
@@ -1856,7 +1856,7 @@ export const Header: React.FC<HeaderProps> = ({
         setIsDevShutdownInFlight(false);
       }
     }
-  }, [isDevShutdownInFlight, setIsDesktopServicesOpen]);
+  }, [isDevShutdownInFlight, runtimeApis.terminal, setIsDesktopServicesOpen]);
 
   const quotaDisplayTabs = React.useMemo(() => {
     return [