feat(gui): add Session Insights panel with token history tracking

src/app_controller.py

@@ -147,6 +147,8 @@ class AppController:
   self._tool_log: List[Dict[str, Any]] = []
   self._tool_stats: Dict[str, Dict[str, Any]] = {}  # {tool_name: {"count": 0, "total_time_ms": 0.0, "failures": 0}}
   self._cached_cache_stats: Dict[str, Any] = {}  # Pre-computed cache stats for GUI
+  self._token_history: List[Dict[str, Any]] = []  # Token usage over time [{"time": t, "input": n, "output": n, "model": s}, ...]
+  self._session_start_time: float = time.time()  # For calculating burn rate
   self._comms_log: List[Dict[str, Any]] = []
   self.session_usage: Dict[str, Any] = {
    "input_tokens": 0,
@@ -961,6 +963,15 @@ class AppController:
    for k in ["input_tokens", "output_tokens", "cache_read_input_tokens", "cache_creation_input_tokens", "total_tokens"]:
     if k in u:
      self.session_usage[k] += u.get(k, 0) or 0
+   input_t = u.get("input_tokens", 0)
+   output_t = u.get("output_tokens", 0)
+   model = payload.get("model", "unknown")
+   self._token_history.append({
+    "time": time.time(),
+    "input": input_t,
+    "output": output_t,
+    "model": model
+   })
 
   if kind in ("tool_result", "tool_call"):
    role = "Tool" if kind == "tool_result" else "Vendor API"
@@ -1753,6 +1764,28 @@ class AppController:
   ai_client.cleanup()
   self._update_cached_stats()
 
+ def get_session_insights(self) -> Dict[str, Any]:
+  import cost_tracker
+  total_input = sum(e["input"] for e in self._token_history)
+  total_output = sum(e["output"] for e in self._token_history)
+  total_tokens = total_input + total_output
+  elapsed_min = (time.time() - self._session_start_time) / 60.0 if self._token_history else 0
+  burn_rate = total_tokens / elapsed_min if elapsed_min > 0 else 0
+  session_cost = cost_tracker.estimate_cost("gemini-2.5-flash", total_input, total_output)
+  completed = sum(1 for t in self.active_tickets if t.get("status") == "complete")
+  efficiency = total_tokens / completed if completed > 0 else 0
+  return {
+   "total_tokens": total_tokens,
+   "total_input": total_input,
+   "total_output": total_output,
+   "elapsed_min": elapsed_min,
+   "burn_rate": burn_rate,
+   "session_cost": session_cost,
+   "completed_tickets": completed,
+   "efficiency": efficiency,
+   "call_count": len(self._token_history)
+  }
+
  def _flush_to_project(self) -> None:
   proj = self.project
   proj.setdefault("output", {})["output_dir"] = self.ui_output_dir