fix(ai-export): strip photo metadata and minimize the training payload

lib/features/session/session_setup_screen.dart

@@ -140,6 +140,7 @@ class _SessionSetupScreenState extends State<SessionSetupScreen> {
         _shotsPerTarget,
         sessionId,
         weaponId: _selectedWeapon!.id,
+        caliber: _selectedWeapon!.caliber,
         distance: _distance,
         date: _selectedDate,
       );