v2026.10.4 — small items from the backlog review

Fifty-four small fixes from the whole-file review of docs/deferred.md (PR #45), across the fleet tools, the citator, the benchmark tools, the text stage and store, and capture and web. Notable: db.migrate checks foreign keys over the tables a migration could reach rather than the whole store (falling back to the full check where the scope cannot see); a fetch capture and its verdict commit together; fetch attachments and capture now require --mode; a declared-empty month is proven against its neighbours when it can be; the caption control asks a second docket before raising a problem; review.item replaces the 10,000-row scans. Nothing a reader sees changes. No migration, no index rebuild: deploy by tag. The fleet's checkout needs tools/fleet/leaseloop.py beside the workers when it next moves.