feat(gui): implement Phases 2-5 of Comprehensive GUI UX track

- Add cost tracking with new cost_tracker.py module
- Enhance Track Proposal modal with editable titles and goals
- Add Conductor Setup summary and New Track creation form to MMA Dashboard
- Implement Task DAG editing (add/delete tickets) and track-scoped discussion
- Add visual polish: color-coded statuses, tinted progress bars, and node indicators
- Support live worker streaming from AI providers to GUI panels
- Fix numerous integration test regressions and stabilize headless service

multi_agent_conductor.py

@@ -22,10 +22,10 @@ class ConductorEngine:
   self.track = track
   self.event_queue = event_queue
   self.tier_usage = {
-   "Tier 1": {"input": 0, "output": 0},
-   "Tier 2": {"input": 0, "output": 0},
-   "Tier 3": {"input": 0, "output": 0},
-   "Tier 4": {"input": 0, "output": 0},
+   "Tier 1": {"input": 0, "output": 0, "model": "gemini-3.1-pro-preview"},
+   "Tier 2": {"input": 0, "output": 0, "model": "gemini-3-flash-preview"},
+   "Tier 3": {"input": 0, "output": 0, "model": "gemini-2.5-flash-lite"},
+   "Tier 4": {"input": 0, "output": 0, "model": "gemini-2.5-flash-lite"},
   }
   self.dag = TrackDAG(self.track.tickets)
   self.engine = ExecutionEngine(self.dag, auto_queue=auto_queue)
@@ -110,7 +110,7 @@ class ConductorEngine:
      await self._push_state(active_tier=f"Tier 3 (Worker): {ticket.id}")
      context = WorkerContext(
       ticket_id=ticket.id,
-      model_name="gemini-2.5-flash-lite",
+      model_name=self.tier_usage["Tier 3"]["model"],
       messages=[]
      )
      # Offload the blocking lifecycle call to a thread to avoid blocking the async event loop.
@@ -268,13 +268,19 @@ def run_worker_lifecycle(ticket: Ticket, context: WorkerContext, context_files:
   if not event_queue:
    return True
   return confirm_execution(payload, event_queue, ticket.id, loop=loop)
+
+ def stream_callback(chunk: str) -> None:
+  if event_queue and loop:
+   _queue_put(event_queue, loop, 'mma_stream', {'stream_id': f'Tier 3 (Worker): {ticket.id}', 'text': chunk})
+
  comms_baseline = len(ai_client.get_comms_log())
  response = ai_client.send(
   md_content=md_content,
   user_message=user_message,
   base_dir=".",
   pre_tool_callback=clutch_callback if ticket.step_mode else None,
-  qa_callback=ai_client.run_tier4_analysis
+  qa_callback=ai_client.run_tier4_analysis,
+  stream_callback=stream_callback
  )
 
  if event_queue: