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/web/server/lib/opencode/settings-helpers.js

@@ -26,6 +26,7 @@ export const createSettingsHelpers = (dependencies) => {
   const SHORTCUT_OVERRIDE_VALUE_MAX_LENGTH = 128;
   const PWA_ORIENTATION_VALUES = new Set(['system', 'portrait', 'landscape']);
   const MOBILE_KEYBOARD_MODE_VALUES = new Set(['native', 'resize-content']);
+  const TERMINAL_SHELL_VALUES = new Set(['auto', 'bash', 'zsh', 'sh', 'fish', 'pwsh', 'powershell', 'cmd', 'dash', 'ksh', 'nu']);
   const HIDDEN_MODELS_MAX = 1024;
   const RECENT_EFFORTS_MAX_KEYS = 128;
   const RECENT_EFFORTS_MAX_VARIANTS_PER_KEY = 5;
@@ -547,6 +548,16 @@ export const createSettingsHelpers = (dependencies) => {
     if (typeof candidate.terminalFontSize === 'number' && Number.isFinite(candidate.terminalFontSize)) {
       result.terminalFontSize = Math.max(9, Math.min(52, Math.round(candidate.terminalFontSize)));
     }
+    if (typeof candidate.terminalShell === 'string') {
+      const shell = candidate.terminalShell.trim().toLowerCase();
+      if (TERMINAL_SHELL_VALUES.has(shell)) result.terminalShell = shell;
+    }
+    if (Array.isArray(candidate.terminalLoginShells)) {
+      result.terminalLoginShells = [...new Set(candidate.terminalLoginShells
+        .filter((shell) => typeof shell === 'string')
+        .map((shell) => shell.trim().toLowerCase())
+        .filter((shell) => TERMINAL_SHELL_VALUES.has(shell)))];
+    }
     if (typeof candidate.padding === 'number' && Number.isFinite(candidate.padding)) {
       result.padding = Math.max(50, Math.min(200, Math.round(candidate.padding)));
     }