fix(reporting): period retirement never resolves the period's open issue occurrences #1886

Summary

Period retirement deletes a period's consumer statements and obligation, but it leaves that period's open or acknowledged reporting_issue_lifecycle occurrences open. Nothing can retire them afterwards. As a result:

• the issue observer never receives a resolved event for them;
• the escalation sweep keeps treating them as live, and after fix(reporting): issue-event retention prune re-escalates still-open occurrences every 7 days #1885's prune deletes their delivered escalated event, it re-escalates them every retention period, forever.

This is the sibling of #1885. The TypeScript SDK found and fixed the same gap in its port (adcontextprotocol/adcp-client#3654 follow-up), where retirement now resolves the period's open occurrences in the retirement transaction.

Where (next @ 74bbe6f)

• period_retirement.py _delete_records (L447-L501) deletes reporting_consumer_statuses, the period's revisions and the reporting_obligations row. It never touches reporting_issue_lifecycle and records no issue event.
• status_projection.py lifecycle_intents (L227-L336) retires a mismatch occurrence only while iterating snapshot.statuses ("retire_mismatch" at L290). Once retirement has deleted the period's statements, no settle can ever reach that occurrence again.
• issue_events.py sweep_escalations (L204+) selects issue_state IN ('open', 'acknowledged') rows with no escalated event. A retired period's occurrence qualifies again as soon as fix(reporting): issue-event retention prune re-escalates still-open occurrences every 7 days #1885's prune removes the delivered escalated row.

Reproduction

1. A mismatch opens and escalates, and both events are delivered.
2. Retention retires the period: its statements and obligation are deleted, and the lifecycle row stays open.
3. No resolved is ever recorded, so the seller's alert never closes.
4. Seven days later, prune deletes the delivered escalated, and the next sweep records and delivers it again, with the same event_id. This repeats indefinitely (fix(reporting): issue-event retention prune re-escalates still-open occurrences every 7 days #1885).

Suggested fix

Inside the retirement transaction, retire the period's live mismatch occurrences: set issue_state = 'resolved' and retired_at, and call record_issue_transition_on so the outbox gets resolved with its usual same-transaction guarantee. Keep the outbox rows, since undelivered events must still go out. The resolved event renders issue=None. The TypeScript fix does exactly this with its existing per-obligation settle.

Python keys occurrences per chain (issue_key), not per obligation. So the retirement needs to resolve the occurrences whose scope (issue_scopes) names the retired obligation, or whose chain identity matches the retired period.

Add a test: an escalated, delivered occurrence of a period retired by retire_expired_periods gets exactly one resolved, is never re-escalated, and is eventually pruned.