feat(notifications): audit-event trail for recap generation + delivery outcome

[JSONbored]

Record an audit event whenever a recap is generated and when each channel delivery succeeds/fails, exactly as generateWeeklyValueReport records weekly_value_report_generated via recordAuditEvent at src/services/weekly-value-report.ts:72. Gives operators a ledger trail ('did the digest send?') without opening the channel. Small, self-contained addition to the recap orchestrator.

Deliverables

• Call recordAuditEvent with a recap_generated event (metadata: cadence, section counts, channels attempted) mirroring src/services/weekly-value-report.ts:72
• Record per-channel delivery outcome (success/failure) as metadata so a swallowed send error is still observable
• Unit test: asserts the audit event is written with the expected eventType + metadata on both success and delivery-failure paths

References

• src/services/weekly-value-report.ts:72
• src/db/repositories.ts

Part of #1963.

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size: XS · held for later release (gittensor:bug once activated)

[linear-code]

JSO-2352