Ran command: git status --short

Ran command: `git diff --cached`
Ran command: `git diff --cached SPECIFICATION.md src/components/layout/AppShell.tsx`

feat(ws): handle nested WS payload envelope and handle assigned conversation events

* Automatically unwrap double-nested WS payloads (`payload.payload`) in `WsClient`.
* Handle `conversation_assigned` WS event in `AppShell` by fetching details via REST.
* Deduplicate `upsertConversation` calls and update conversation handling logic.
* Add comprehensive test suites for WS unwrapping and store deduplication.

src/services/wsClient.ts

@@ -105,7 +105,7 @@ class WsClient {
 
     this.ws.onmessage = (event: MessageEvent) => {
       try {
-        const data = JSON.parse(event.data as string);
+        let data: Record<string, unknown> = JSON.parse(event.data as string);
 
         // Handle auth response first
         if (data.status === 'authenticated') {
@@ -125,6 +125,24 @@ class WsClient {
           return;
         }
 
+        // Normalizar doble envoltura (nested envelope del backend)
+        // El backend envía: { type, eventId, payload: { type, eventId, payload: { datos } } }
+        // Debemos aplanar a: { type, eventId, payload: { datos } }
+        if (
+          data.payload &&
+          typeof data.payload === 'object' &&
+          !Array.isArray(data.payload) &&
+          !data.status && // NUNCA para mensajes de control como {"status":"authenticated"}
+          (data.payload as Record<string, unknown>).type &&
+          (data.payload as Record<string, unknown>).payload
+        ) {
+          // Conservar el type y eventId externos, usar el payload interno
+          data = {
+            ...data,
+            payload: (data.payload as Record<string, unknown>).payload,
+          };
+        }
+
         // Delegate business events to registered callback
         if (this.onMessageCallback) {
           const envelope: WSEnvelope = data;