refactor: split app.js into focused frontend modules (phase 5)

Extract 8 modules from the 15K-line app.js monolith:
- constants.js: shared constants, timing, escapeHtml(), extractSyncSegments()
- mobile-handlers.js: MobileDetection, KeyboardHandler, SwipeHandler
- voice-input.js: DeepgramProvider, VoiceInput
- notification-manager.js: NotificationManager class
- keyboard-accessory.js: KeyboardAccessoryBar, FocusTrap
- api-client.js: _api(), _apiJson(), _apiPost(), _apiDelete() helpers
- subagent-windows.js: 13 subagent window methods (open, close, drag, lines)
- vendor/xterm-zerolag-input.js: IIFE build replacing inlined copy

app.js reduced from ~15,200 to ~11,500 lines. All modules use global
scope with <script defer> ordering. Prototype extensions use
Object.assign(CodemanApp.prototype, {...}) pattern.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/xterm-zerolag-input/package.json

@@ -17,7 +17,7 @@
     "dist/"
   ],
   "scripts": {
-    "build": "tsup src/index.ts --format cjs,esm --dts --clean",
+    "build": "tsup",
     "test": "vitest run",
     "typecheck": "tsc --noEmit",
     "prepublishOnly": "npm run build"

packages/xterm-zerolag-input/tsup.config.ts

@@ -0,0 +1,33 @@
+import { defineConfig } from 'tsup';
+
+export default defineConfig([
+  // Standard builds (CJS + ESM + DTS)
+  {
+    entry: ['src/index.ts'],
+    format: ['cjs', 'esm'],
+    dts: true,
+    clean: true,
+  },
+  // IIFE build for browser <script> tag usage
+  {
+    entry: ['src/index.ts'],
+    format: ['iife'],
+    globalName: 'XtermZerolagInput',
+    outDir: 'dist',
+    // Append global aliases so app.js can access classes directly
+    footer: {
+      js: [
+        '// Global aliases for browser usage',
+        'if(typeof window!=="undefined"){',
+        '  window.ZerolagInputAddon=XtermZerolagInput.ZerolagInputAddon;',
+        '  window.LocalEchoOverlay=class extends XtermZerolagInput.ZerolagInputAddon{',
+        '    constructor(terminal){',
+        '      super({prompt:{type:"character",char:"\\u276f",offset:2}});',
+        '      this.activate(terminal);',
+        '    }',
+        '  };',
+        '}',
+      ].join('\n'),
+    },
+  },
+]);