test(maestro): update tests for async structured spawn

Tests now assert `Starting` after create and use `wait_for_ready`
before checking post-handshake state. Unsupported command test
expects `BadRequest` instead of a persisted Dead session.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/types.ts

@@ -11,7 +11,7 @@ export type SessionStatus = "Running" | "Dead";
 /** Daemon-inferred activity dimension, orthogonal to `SessionStatus` (NAP-340).
  * Absent on payloads from daemons that predate the field. `Error` is only set
  * when an agent reports failure (#105); the daemon never infers it. */
-export type ActivityState = "Active" | "Idle" | "AwaitingInput" | "Error";
+export type ActivityState = "Active" | "Idle" | "AwaitingInput" | "Error" | "Starting";
 
 export interface Session {
   id: Uuid;