- write-back: call upsert_tag inside _apply_tag's try so a tag-create failure
is caught per-asset and apply_all no longer aborts mid-batch (was P1)
- write-back: surface _pipeline/processed write failures in the result instead
of discarding them (was reported as success)
- ui: add title to the high confidence badge so approve-high-confidence's
pre-action count is non-zero; confirm() before single-cluster apply
- core: Store context manager; close DB connection even if a route raises;
guard split_cluster against a first-member boundary (empty cluster); add
writeback_log lookup index
- ingest: split thumbnail download/write error handling and clean up the
.tmp file on a write failure
- tests: upsert/processed write-failure regression tests + split-guard test