chore: update .gitignore, CLAUDE.md, training_log.json, and ml_filter.py

- Added .worktrees/ to .gitignore to prevent tracking of worktree files.
- Marked `optuna-precision-objective-plan` as completed in CLAUDE.md.
- Added new training log entry for a LightGBM model with updated parameters and performance metrics in training_log.json.
- Updated error handling in ml_filter.py to return False on prediction errors instead of True, improving the robustness of the ML filter.

.gitignore

@@ -12,4 +12,6 @@ models/tune_results_*.json
 data/*.parquet
 .worktrees/
 .DS_Store
-.cursor/
+.cursor/
+
+.worktrees/