Polish: concept top-2 calibration, cross-cutting tag, uncertainty flag, overall depth bar

Deploy: Dockerfile, slim requirements, Space config

Phase 8: provider toggle, layout fix, markdown rendering

Phase 4b: DistilBERT in-domain 0.952, OOD 0.916, degradation halved vs LogReg

Phase 4a: classical models, ladder 0.167/0.636/0.928

Phase 2: dedup and stratified splits, near-dup rate 0.4%

Phase 0-1: project scaffold and data procession