fix(integrations): preserve Slack Content correction across runtime gaps - #5721

Problem

In a production Slack→Content correction, Content updated the existing Design Ask, but Dispatch never posted the final Slack reply. The task, campaign, and A2A continuation became terminal failed three seconds after a continuation self-dispatch TLS error, with Durable integration campaign was disabled for this scope. The same terminal reason occurred in the test channel on September 1. A scheduled retry cannot recover a terminal row after its continuation identity has been cleared.

The durable-dispatch check currently treats two different conditions alike: an explicit rollout shutdown and a temporarily unavailable runtime prerequisite. That makes a transient host/config mismatch destroy already-started work, even if the downstream edit succeeded.

Change

• Declare the durable-dispatch flag in server app config so all runtime readers use one typed setting.
• Distinguish an explicit flag-off or scope removal from unavailable runtime prerequisites (flag not present, background route unavailable, or A2A secret unavailable).
• Keep an already-started A2A continuation and campaign recoverable during the latter; reschedule the continuation and log only non-secret reason categories. Explicit rollout disable still fails closed.
• Return the no-op claim attempt when pausing. Move temporarily unavailable campaign and A2A work out of each bounded recovery scan, and prioritize receipt-confirmed A2A owners. The A2A deferral is one bulk update, not a database round trip per task.
• Preserve the same distinction in the A2A sweep, campaign sweep, and signed campaign continuation route.

This does not resurrect the already-terminal production correction; it prevents that loss on future work. The companion workspace PR #1278 emits the scheduled recovery function, but must not be treated as the full Slack fix until this Core release is consumed and a fresh human-interface create-and-correct test passes.

Proof and remaining gate

• Focused Core tests: 195 passed across config, durable dispatch, continuation, campaign recovery, and plugin routes. After the review fixes, all 156 tests across the four changed recovery/store suites passed, including 35 consecutive runtime pauses without consuming a remote-poll attempt and a full 200-owner unavailable scan window that leaves later work reachable.
• A two-step regression pauses an already-started continuation without contacting Content, then resumes it by polling the same persisted downstream A2A task ID and delivers the Slack response. No second message/send client is available in that processor test.
• Core typecheck, diff check, and all 77 repository guards pass.
• The revised grouped, receipt-first recovery query parsed successfully against an in-memory PostgreSQL-compatible engine.
• This is local proof, not deployed acceptance. Publish this package, update the workspace dependency, deploy, and verify one Content item, its follow-up correction, and the final Slack reply before calling the flow fixed.

content_product_impact:
  lane: contract_repair
  features:
    - content.feature.durable-foundations
  capabilities:
    - content.agent.action-parity
  record_change: none
  proof:
    - pnpm --filter @agent-native/core exec vitest --run src/integrations/a2a-continuation-processor.spec.ts
  rationale: Preserve one canonical Content mutation while its cross-app Slack acknowledgement recovers.