Missed smoke on annotated alerts: no recovery path once the alert is done

Gap

A reviewer on /localize/done/:id who spots smoke the AI (and both passes) missed can record it — the missed-smoke row PATCHes has_missed_smoke (since #312) — but nothing acts on it:

• Skip alert is queue-only by design: POST /alert/skip 409s when every lane is ANNOTATED ("Alert is fully annotated — nothing to skip"). A skip row on a done alert would be visible in neither queue.
• Add object is retired until the drawing flow is ready (#312), and was the only mechanism that could re-open a done alert.

So an annotated-but-wrong alert is stuck: complete by stage, known-incomplete by flag.

Option considered and rejected: demote-then-skip

Move lanes back to a pre-annotated stage so the alert passes the skip guard and lands in the Skipped view. Rejected because:

• The skip overlay is deliberately insert-only and never touches lane state (its whole safety story); pairing it with stage demotion inverts that and makes unskip lossy.
• Lane stages feed other machinery (sibling auto-annotation fan-out, group sweep, done-list queries); rewinding ANNOTATED lanes risks retriggering it.
• After unskip the alert returns to the localize queue, where the only real fix (drawing the missed object) still doesn't exist.

Proposed shape: the flag is the backlog

• Keep skip queue-only, untouched.
• Treat ANNOTATED && has_missed_smoke as its own small backlog: a "Flagged after done" view or filter on the localize done list — the Skipped view's sibling, not its tenant. No schema change needed; the flag is already recorded.
• When add-object ships, that backlog is the worklist: adding a lane to a done alert spawns it at the bbox stage, so the alert is no longer fully annotated and re-enters the localize queue via the existing predicate — no demotion of finished lanes.

Related

• #312 (retire add-object, nudge toward skip)
• #297 (alert skip escape hatch)
• #275 / #288 (FP→smoke promote — same "revise a settled decision" family)

Start by tracing /localize/done/:id, the missed-smoke PATCH for has_missed_smoke, and the done-list predicates; compare them with the /alert/skip fully-annotated guard. Done means annotated alerts flagged after completion appear in a separate backlog or filter and can later re-enter through add-object without demoting finished lanes.