feat(mma): Phase 1 — source_tier tagging at emission

- ai_client: add current_tier module var; stamp source_tier on every _append_comms entry
- multi_agent_conductor: set current_tier='Tier 3' around send(), clear in finally
- conductor_tech_lead: set current_tier='Tier 2' around send(), clear in finally
- gui_2: _on_tool_log captures current_tier; _append_tool_log stores dict with source_tier
- tests: 8 new tests covering current_tier, source_tier in comms, tool log dict format

multi_agent_conductor.py

@@ -308,6 +308,7 @@ def run_worker_lifecycle(ticket: Ticket, context: WorkerContext, context_files:
    old_comms_cb(entry)
 
  ai_client.comms_log_callback = worker_comms_callback
+ ai_client.current_tier = "Tier 3"
  try:
   comms_baseline = len(ai_client.get_comms_log())
   response = ai_client.send(
@@ -320,7 +321,7 @@ def run_worker_lifecycle(ticket: Ticket, context: WorkerContext, context_files:
   )
  finally:
   ai_client.comms_log_callback = old_comms_cb
-
+  ai_client.current_tier = None
  if event_queue:
   # Push via "response" event type — _process_event_queue wraps this
   # as {"action": "handle_ai_response", "payload": ...} for the GUI.