feat: server config, token client, TLS pinning, connection test (Phase 1)

ServerConfig parses https base URL and derives wss livekit URL;
TokenClient POSTs /token with clean 503/offline error states;
TLSPinning holds optional cert SHA-384 pins (empty = system trust);
Settings gains a Connection test screen proving the endpoint works.

.xcodebuildmcp/config.yaml

@@ -1,4 +1,5 @@
 schemaVersion: 1
+enabledWorkflows: ["simulator", "ui-automation"]
 sessionDefaults:
   projectPath: /Users/shane/dev/voice-ios/Voice.xcodeproj
   scheme: Voice_iOS