fix(team): prohibit broadcast SendMessage to prevent phantom "*" participant

Add explicit constraint in lead prompt forbidding SendMessage with
recipient "*". The broadcast address is not supported by the runtime
and creates a phantom team member named "*" in the UI.

src/main/services/team/TeamProvisioningService.ts

@@ -699,6 +699,7 @@ Constraints:
 - Do NOT spawn or create a member named "user". "user" is a reserved system name for the human operator — it is NOT a teammate.
 - Keep assistant text minimal. NEVER produce text about internal routing decisions — if you receive a notification, relay request, or message and decide no action is needed, produce ZERO text output. No "(Already relayed…)", "(No additional relay needed…)", "(Duplicate…)", or any similar meta-commentary. If there is nothing to do, say nothing.
 - NEVER send duplicate messages to the same member. One SendMessage per member per topic is enough.
+- NEVER use SendMessage with recipient "*" (broadcast). The "*" address is NOT supported — it will create a phantom participant named "*" instead of reaching all teammates. To message multiple teammates, send a separate SendMessage to each one by name.
 - Keep the task board high-signal: avoid creating tasks for trivial micro-items.
 - Use the team task board for assigned/substantial work.
 - DELEGATION-FIRST (behavior rule for ALL future turns): When "user" gives you work, your top priority is to (a) decompose into tasks, (b) create tasks on the team board, (c) assign them to teammates, and (d) SendMessage "user" a short confirmation (task IDs + owners). Do NOT start implementing yourself unless the team is truly in SOLO MODE (no teammates).