fix(reset): clear mma_tier_usage and RAG state in _handle_reset_session

src/app_controller.py

@@ -3378,6 +3378,16 @@ class AppController:
   self.active_tickets = []
   self.engines.clear()
   self.mma_streams.clear()
+  # Reset mma_tier_usage to pre-populated default (prior tests pollute it)
+  self.mma_tier_usage = {'Tier 1': {}, 'Tier 2': {}, 'Tier 3': {}, 'Tier 4': {}}
+  # Reset RAG engine state so the chroma collection from a prior test
+  # doesn't leak into the next session. The next _sync_rag_engine will
+  # rebuild the engine with the new active_project_root.
+  self.rag_engine = None
+  self.rag_config = None
+  self.rag_status = 'idle'
+  self._rag_sync_token = 0
+  self._rag_sync_dirty = False
   self._worker_status.clear()
   self._current_provider = "gemini"
   self._current_model = "gemini-2.5-flash-lite"