feat(app_controller): reset project state in _handle_reset_session

Stale project state from prior live_gui tests (shared session-scoped
subprocess) was leaking into subsequent tests, causing the
test_full_live_workflow race condition: 'Project not switched' errors
when self.project still claimed to be a different project.

The fix: _handle_reset_session now mirrors the default-project branch
of __init__ (lines 1743-1745), creating a fresh default project dict,
clearing active_project_path and project_paths, and reinitializing
the workspace manager.

- src/app_controller.py: 6 new lines in _handle_reset_session
- tests/test_handle_reset_session_clears_project.py: 3 tests
  (active_project_path, project_paths, self.project)

src/app_controller.py

@@ -3266,6 +3266,15 @@ class AppController:
   discussions = disc_sec.get("discussions", {})
   for d_name in discussions:
    discussions[d_name]["history"] = []
+  # Reset project state so stale data from prior live_gui tests does not
+  # leak into the next session. Mirrors the default-project branch in
+  # __init__ (see lines 1743-1745).
+  reset_name = Path(self.active_project_path).stem if self.active_project_path else "unnamed"
+  self.project = project_manager.default_project(reset_name)
+  self.active_project_path = ""
+  self.project_paths = []
+  self.workspace_manager  = workspace_manager.WorkspaceManager(project_root=None)
+  self.workspace_profiles = self.workspace_manager.load_all_profiles()
   self.ai_status = "session reset"
   self.ai_response = ""
   self.ui_ai_input = ""