feat: pairing v2 — one-tap trusted devices over LAN and private relay (#2103)

Reworks how devices connect to an OpenChamber server, end to end.

Pairing v2:
- One-time pairing links/QR codes (openchamber://connect?v=2) carrying a set of transport candidates (LAN/tunnel/relay) and a single-use secret redeemed server-side; no tokens embedded in links
- Add-a-device dialog written for first-time users: intent-based transport choice (Anywhere / Home network only / This computer only) with plain-language descriptions, transparent fallback checkboxes, server-authoritative LAN detection, high-res QR dialog
- Private relay folded into pairing as a transport candidate with a demand-driven lifecycle (enables when a relay device is paired, disables when none remain)

Multi-transport devices:
- A saved device holds all its transports and one token; mobile re-probes on connect, resume, and network change and hot-switches LAN<->relay seamlessly (no re-pairing, no remount, session preserved)
- Desktop can import relay pairing links, switch to relay hosts through the E2EE tunnel, and restore a relay default host after relaunch

Device management:
- Device list (web + desktop) shows live per-device connectivity with the active transport (Connected - Local network / Relay) and platform badges (iOS/Android/macOS/Windows/Linux)
- One physical device = one record: stable per-install dedupe keys across pairing and password re-login; typed pairing label names the device, paired devices name the connection by the issuing server hostname
- Trusted desktop-local client manages all devices (list, revoke, clear revoked); relay host reaps dead client sockets after 3 missed keepalives

Android:
- LAN transport unblocked (cleartext + mixed content, mirroring iOS ATS exceptions); resume re-probe retries through network flux and silently auto-reconnects from a disconnected state

packages/ui/src/apps/runtimeEndpointReset.ts

@@ -9,6 +9,20 @@ import { useUIStore } from '@/stores/useUIStore';
 import { useSessionUIStore } from '@/sync/session-ui-store';
 import { resetStreamingState } from '@/sync/streaming';
 
+// Same-device transport switch (LAN⇄relay for one paired device): rebind the SDK
+// to the new transport WITHOUT tearing down connection/session state or remounting
+// the sync layer. `reconnectToRuntimeBaseUrl` swaps in a fresh SDK client; the
+// caller then forces a re-render so SyncProvider receives it as a new `sdk` prop,
+// which re-runs its event-pipeline + bootstrap effects (keyed on `sdk`) to
+// reconnect over the new transport IN PLACE. Message-pagination refs, the open
+// session, and the whole view are preserved — no reconnecting screen, no flash,
+// no bounce back to the draft.
+export const reconnectAppForTransportSwitch = (): void => {
+  disposeTerminalInputTransport();
+  opencodeClient.reconnectToRuntimeBaseUrl();
+  resetStreamingState();
+};
+
 export const resetAppForRuntimeEndpointChange = (detail: RuntimeEndpointChangedDetail): void => {
   useSessionUIStore.getState().prepareForRuntimeSwitch(detail.previousRuntimeKey);
   useUIStore.getState().prepareForRuntimeSwitch(detail.previousRuntimeKey);