Remove redundant detect_scenario from LossDebugger

Fix false/inaccurate citations in LossDebugger

Fix LR reference table and batch-LR scaling guidance in LossDebugger

Fix batch size diagnostic: widen window and list multiple causes

Fix gradient diagnostic thresholds with evidence-based criteria in LossDebugger

Fix check_numerical_stability accuracy and completeness

Scale overfit test LR and steps by model size in LossDebugger

Reduce LOSS_BOUNCE false positives with moving-average smoothing

Improve LOSS_BOUNCE detection with pre-computed bounce metrics

Add LOSS_BOUNCE detection to diagnose_status classification chain

Add NaN detection to diagnose_status classification chain

Fix debugger reference data and scenario detection logic

Tighten expected loss ranges for FineWeb-Edu dataset

feat(training): add LossDebugger 5-level diagnostic framework