Assistant: reliable "Nueva conversación" reset

Clearing in place (setMessages + remount) left the conversation
rendered — CopilotKit keeps chat state beyond agent.messages — so the
button now reloads the page after deleting the thread: a fresh boot
hydrates from the empty store and shows the welcome screen with
suggestions, which previously only appeared after a manual refresh.

Supporting changes:
- CopilotChat gets an explicit agentId="wealthysmart" (without it, it
  resolves DEFAULT_AGENT_ID and can bind a different client agent
  instance than useAgent's).
- The BFF answers CopilotChat's POST …/connect with an
  immediately-completed stream: the runtime's in-memory runner replays
  this PROCESS's event history, which resurrects cleared conversations
  and double-feeds hydration. The empty-messages hydration run against
  the DB store is the single restore path.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/pages/Asistente.tsx

@@ -82,11 +82,13 @@ export default function Asistente() {
         method: "DELETE",
         credentials: "include",
       });
-      agent?.setMessages([]);
-      setConfirmClear(false);
+      // Full reload is the reliable reset: CopilotKit keeps chat state in
+      // more places than agent.messages (clearing it in place left the
+      // conversation rendered), while a fresh boot hydrates from the
+      // now-empty store and shows the welcome screen + suggestions.
+      window.location.reload();
     } catch (err) {
       console.error("[asistente] clear thread failed:", err);
-    } finally {
       setClearing(false);
     }
   };
@@ -165,6 +167,11 @@ export default function Asistente() {
       <div className="flex-1 min-h-0 rounded-xl border border-border overflow-hidden bg-card">
         <CopilotChat
           className="h-full"
+          // Without an explicit agentId, CopilotChat resolves DEFAULT_AGENT_ID
+          // ("default") — a DIFFERENT client agent instance than
+          // useAgent({agentId:"wealthysmart"}); clearing one leaves the other
+          // rendering its own copy of the conversation.
+          agentId="wealthysmart"
           threadId={CHAT_THREAD_ID}
           labels={{
             modalHeaderTitle: "WealthySmart",