feat(android): QR pairing — scan, deep link, one-step auto-login

Companion side of docs/companion-pairing-qr.md (v1 contract):
- Connect screen lands on Scan Node's QR / Enter Manually; NESMenu gains
  an add-server-by-QR icon button
- QrScannerOverlay: CameraX + ZXing core (pinned, on-device, no ML Kit)
- ServerQrParser: archipelago://pair?v=1&url=..[&pw=..]; unknown major v
  -> 'update the app'; upsert by origin so re-scans never duplicate
- archipelago:// deep link registered (singleTask + onNewIntent) for the
  modal's 'Open in companion app' button
- WebView auto-fills and submits Login.vue's password form when a stored
  password exists — demo QR is one step to a logged-in session
- Web modal + handoff doc copy synced to the real label: Scan Node's QR
- v0.4.13 (versionCode 17)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

neode-ui/src/components/CompanionIntroOverlay.vue

@@ -86,7 +86,7 @@
                 <div class="min-w-0 flex-1">
                   <h3 class="text-lg font-semibold text-white mb-1">Connect your app</h3>
                   <p class="text-sm text-white/60 leading-relaxed">
-                    In the companion app, choose “Scan node code” and point your phone here — the server details fill in automatically.
+                    In the companion app, choose “Scan Node's QR” and point your phone here — the server details fill in automatically.
                   </p>
                 </div>
               </div>