feat: redesign remote tunnel settings and named tunnel workflow (#546)

* feat: add Cloudflare Tunnel settings for desktop app

Add a 'Remote Tunnel' section in Settings (desktop-only) that lets users
start/stop a Cloudflare quick tunnel on demand, with auto-generated
password protection and a QR code for easy mobile access.

- Server: 4 new API endpoints (check/status/start/stop) reusing the
  existing cloudflare-tunnel module
- UI: TunnelSettings component with full state machine
  (checking → idle/not-available → starting → active → stopping)
- QR code rendered via the qrcode package for in-app display
- Hidden from VS Code extension (desktop/web only)

* fix: use ?token= instead of ?p= in tunnel password URLs

REST API endpoints were building passwordUrl with ?p=<token> but
SessionAuthGate reads the ?token= query param, causing QR code
auto-login to fail — the password was never extracted from the URL.

Standardize all three tunnel URL construction sites to use ?token=
so scanning the QR code correctly pre-fills and submits the password.

* feat: secure remote tunnel access with one-time connect links

* feat: redesign remote tunnel settings and access flow

* fix: cleaned up unused desktop close code path

* feat: overhaul named tunnel setup and persistence flow

* chore: align codemirror language dependency resolution

---------

Co-authored-by: Brian-Hwang <brian.hwang@cornelisnetworks.com>

packages/ui/package.json

@@ -68,6 +68,7 @@
     "motion": "^12.23.24",
     "next-themes": "^0.4.6",
     "prismjs": "^1.30.0",
+    "qrcode": "^1.5.4",
     "react": "^19.1.1",
     "react-dom": "^19.1.1",
     "react-syntax-highlighter": "^15.6.6",
@@ -86,6 +87,7 @@
     "@tauri-apps/api": "^2.9.0",
     "@types/node": "^24.3.1",
     "@types/prismjs": "^1.26.6",
+    "@types/qrcode": "^1.5.5",
     "@types/react": "^19.1.10",
     "@types/react-dom": "^19.1.7",
     "@vitejs/plugin-react": "^5.0.0",