chore: clean codebase for production

perf: optimize deps, imports, Dockerfile; improve README for judges

feat: source-based gating for authenticity override

fix: scope authenticity override to realtime-only, preserve file upload AI detection

fix: final calibration - auth override 40, anomaly multiplier 0.55, P4 avg-risk label

fix: round 3 recalibration - widen override and fix session labelling

fix: aggressive recalibration for browser mic human voice detection

fix: model confidence calibration for browser mic audio

fix: complete 24-issue compatibility audit (C1-C4, H1-H4, M1-M11, L1-L5)

refactor: detect label inversion once at load time, reduce log noise

fix: P1-P11 comprehensive risk scoring, signal calibration, and session summary improvements

fix: invert label mapping for primary model (training labels were swapped)

fix: correct id2label key-type mismatch causing inverted classifications