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

conductor_tech_lead.py

@@ -19,6 +19,7 @@ def generate_tickets(track_brief: str, module_skeletons: str) -> list[dict]:
  # Set custom system prompt for this call
  old_system_prompt = ai_client._custom_system_prompt
  ai_client.set_custom_system_prompt(system_prompt)
+ ai_client.current_tier = "Tier 2"
  try:
  # 3. Call Tier 2 Model
   response = ai_client.send(
@@ -41,11 +42,11 @@ def generate_tickets(track_brief: str, module_skeletons: str) -> list[dict]:
   return tickets
  except Exception as e:
   print(f"Error parsing Tier 2 response: {e}")
-  # print(f"Raw response: {response}")
   return []
  finally:
- # Restore old system prompt
+ # Restore old system prompt and clear tier tag
   ai_client.set_custom_system_prompt(old_system_prompt)
+  ai_client.current_tier = None
 
 from dag_engine import TrackDAG
 from models import Ticket