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/web/server/lib/opencode/bootstrap-runtime.js

@@ -22,6 +22,11 @@ export const createBootstrapRuntime = (dependencies) => {
       uiPassword,
       tunnelAuthController,
       remoteClientAuthRuntime,
+      clientPairingRuntime,
+      getRelayPairingCandidate,
+      reconcileRelay,
+      getPairingTransports,
+      getServerLabel,
       readSettingsFromDiskMigrated,
       normalizeTunnelSessionTtlMs,
       sayTTSCapability,
@@ -82,6 +87,11 @@ export const createBootstrapRuntime = (dependencies) => {
       tunnelAuthController,
       uiAuthController,
       remoteClientAuthRuntime,
+      clientPairingRuntime,
+      getRelayPairingCandidate,
+      reconcileRelay,
+      getPairingTransports,
+      getServerLabel,
       readSettingsFromDiskMigrated,
       normalizeTunnelSessionTtlMs,
     });