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/DOCUMENTATION.md

@@ -123,7 +123,7 @@ This module provides OpenCode server integration utilities for the web server ru
   - `resolveWslExecutablePath()`
   - `buildWslExecArgs(execArgs, distroOverride?)`
   - `isExecutable(filePath)`
-  - `searchPathFor(binaryName)`
+  - `searchPathFor(binaryName, searchPath?)`: resolves an executable from the supplied PATH value, defaulting to the process PATH.
   - `clearResolvedOpenCodeBinary()`
 
 ## Public exports (env-config.js)

packages/web/server/lib/opencode/env-runtime.js

@@ -87,14 +87,13 @@ export const createOpenCodeEnvRuntime = (deps) => {
     return isExecutable(trimmed) ? trimmed : null;
   };
 
-  const searchPathFor = (binaryName) => {
+  const searchPathFor = (binaryName, searchPath = process.env.PATH || '') => {
     const trimmed = typeof binaryName === 'string' ? binaryName.trim() : '';
     if (!trimmed) {
       return null;
     }
 
-    const current = process.env.PATH || '';
-    const parts = current.split(path.delimiter).filter(Boolean);
+    const parts = searchPath.split(path.delimiter).filter(Boolean);
     const candidateNames = [];
 
     if (process.platform === 'win32' && !path.extname(trimmed)) {

packages/web/server/lib/opencode/env-runtime.test.js

@@ -118,6 +118,19 @@ const createRuntime = (settings, options = {}) => {
 };
 
 describe('OpenCode env runtime', () => {
+  it('searches an explicit PATH without mutating the process environment', () => {
+    const defaultDir = createTempDir('openchamber-default-path-');
+    const explicitDir = createTempDir('openchamber-explicit-path-');
+    const binary = path.join(explicitDir, process.platform === 'win32' ? 'custom-shell.exe' : 'custom-shell');
+    fs.writeFileSync(binary, '#!/bin/sh\nexit 0\n');
+    if (process.platform !== 'win32') fs.chmodSync(binary, 0o755);
+    process.env.PATH = defaultDir;
+    const { runtime } = createRuntime({});
+
+    expect(runtime.searchPathFor('custom-shell', explicitDir)).toBe(binary);
+    expect(process.env.PATH).toBe(defaultDir);
+  });
+
   it('throws a specific error for a missing configured OpenCode binary in strict mode', async () => {
     const { runtime } = createRuntime({ opencodeBinary: '/missing/opencode' });
 

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)));
     }

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

@@ -78,6 +78,19 @@ describe('settings helpers', () => {
     expect(helpers.sanitizeSettingsUpdate({ messageStreamTransport: 'websocket' })).toEqual({});
   });
 
+  it('sanitizes the persisted terminal shell', () => {
+    const helpers = createTestHelpers();
+
+    expect(helpers.sanitizeSettingsUpdate({ terminalShell: ' ZSH ' })).toEqual({ terminalShell: 'zsh' });
+    expect(helpers.sanitizeSettingsUpdate({ terminalShell: 'auto' })).toEqual({ terminalShell: 'auto' });
+    expect(helpers.sanitizeSettingsUpdate({ terminalShell: '/bin/zsh' })).toEqual({});
+    expect(helpers.sanitizeSettingsUpdate({ terminalShell: 'zsh -c whoami' })).toEqual({});
+    expect(helpers.sanitizeSettingsUpdate({ terminalLoginShells: [' ZSH ', 'bash', 'zsh', '/bin/fish', 42] })).toEqual({
+      terminalLoginShells: ['zsh', 'bash'],
+    });
+    expect(helpers.sanitizeSettingsUpdate({ terminalLoginShells: [] })).toEqual({ terminalLoginShells: [] });
+  });
+
   it('accepts desktopLanAccessEnabled as a persisted shared setting', () => {
     const helpers = createTestHelpers();