Ingestion: Home Assistant WebSocket push path

HomeAssistantWebSocketWorker holds a persistent state_changed subscription per HA endpoint that opts in via the connector's WebSocket toggle (HaEndpointConfig.UseWebSocket): auth handshake, subscribe, ingest in real time, capped-backoff reconnect. The REST poll worker skips WS endpoints so each is served once. HaWebSocketProtocol holds the pure handshake/parse logic. Verified by 11 protocol unit tests + a live integration test against an in-process fake HA server. CLAUDE.md updated.

Claude-Session: https://claude.ai/code/session_01Kib2MniVFbD95fkgLgBBnB

src/Infrastructure/Ingestion/HaEndpointConfig.cs

@@ -22,6 +22,13 @@ public sealed record HaEndpointConfig
     /// <summary>Name of the environment variable holding the long-lived access token.</summary>
     public string? TokenEnv { get; init; }
 
+    /// <summary>
+    /// When true, a persistent WebSocket subscription pushes state changes in real time
+    /// (<see cref="HomeAssistantWebSocketWorker"/>); when false (default) the REST poll worker
+    /// samples on each source's interval. An endpoint is handled by exactly one of the two.
+    /// </summary>
+    public bool UseWebSocket { get; init; }
+
     public static HaEndpointConfig Parse(string? json)
     {
         if (string.IsNullOrWhiteSpace(json))