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>

package.json

@@ -123,6 +123,7 @@
     "zustand": "^5.0.8"
   },
   "overrides": {
+    "@codemirror/language": "6.12.2",
     "@codemirror/view": "6.39.13"
   },
   "devDependencies": {