feat: HuggingFace model management tab
- New /api/models router: HF lookup, approval queue (JSONL persistence),
SSE download progress via snapshot_download(), installed model listing,
path-traversal-safe DELETE
- pipeline_tag → adapter type mapping (zero-shot-classification,
sentence-similarity, text-generation)
- 27 tests covering all endpoints, duplicate detection, path traversal
- ModelsView.vue: HF lookup + add, approval queue, live download progress
bars via SSE, installed model table with delete
- Sidebar entry (🤗 Models) between Benchmark and Corrections