fix(tui): normalize session key to lowercase to match gateway canonicalization (#34013)

Merged via squash.

Prepared head SHA: cfe06ca131
Co-authored-by: lynnzc <6257996+lynnzc@users.noreply.github.com>
Co-authored-by: altaywtf <9790196+altaywtf@users.noreply.github.com>
Reviewed-by: @altaywtf

src/tui/tui.ts

@@ -203,9 +203,9 @@ export function resolveTuiSessionKey(params: {
     return trimmed;
   }
   if (trimmed.startsWith("agent:")) {
-    return trimmed;
+    return trimmed.toLowerCase();
   }
-  return `agent:${params.currentAgentId}:${trimmed}`;
+  return `agent:${params.currentAgentId}:${trimmed.toLowerCase()}`;
 }
 
 export function resolveGatewayDisconnectState(reason?: string): {