Add Ghostty terminal, session recovery, voice asset caching, and gitignore large assets

Integrates ghostty-web and node-pty packages, adds tmux session recovery on startup,
refactors WebSocket transport to noServer mode, caches Sherpa voice model assets via
service worker. Large assets (sherpa, ghostty-vt.wasm, fonts) are now gitignored as
they are copied from the webterm project.

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

package.json

@@ -47,9 +47,11 @@
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "express": "^5.1.0",
+    "ghostty-web": "^0.4.0",
     "jsonwebtoken": "^9.0.2",
     "lucide-react": "^0.577.0",
     "multer": "^2.1.1",
+    "node-pty": "^1.1.0",
     "react": "^19.1.0",
     "react-dom": "^19.1.0",
     "react-markdown": "^10.1.0",
@@ -84,6 +86,7 @@
     "bcrypt@6.0.0": true,
     "better-sqlite3@12.10.0": true,
     "esbuild@0.28.0": true,
-    "esbuild@0.25.12": true
+    "esbuild@0.25.12": true,
+    "node-pty@1.1.0": true
   }
 }