[Fix] Session follow-ups disappear during active responses

[roomote-roomote]

​Opened on behalf of @daniel-lxs. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

What changed

• Human follow-ups are persisted in the durable Fast parent-event inbox before web, Teams, Telegram, Slack, or Discord reports success.
• Teams and Telegram route admitted follow-ups through the durable queue without holding webhook requests open for inference, and release ingress dedupe claims when admission fails so provider retries can persist the message.
• Queued human turns construct MCP, task-launch, and suggestion adapters for the follow-up author rather than the Session owner.
• Stable provider identities deduplicate retries, and focused tests cover admission failures, retry claims, provider deadlines, actor attribution, queue ordering, finalization, and attachments.

Why this change was made

A Session follow-up could be accepted and recorded at ingress while another response was active, yet still lack a durable or correctly authorized path to inference. This reliability change closes that post-ingress loss window without adding native steering.

Impact

Messages sent while a Session is responding are durably retained before success is reported, provider retries remain usable after admission failures, and each message runs in a subsequent turn under its actual author.

Related PRs

• #1955: native OpenCode steering builds on this reliability fix.

[roomote-community]

No code issues found. See task

• apps/api/src/handlers/telegram/index.ts:601 and apps/api/src/handlers/teams/index.ts:2120 still acknowledge shared-surface follow-ups before durable admission completes.
• apps/api/src/handlers/telegram/index.ts:597 and apps/api/src/handlers/teams/index.ts:2120 consume webhook retries with their pre-admission duplicate claims after an admission failure.
• apps/api/src/handlers/telegram/index.ts:597 and apps/api/src/handlers/teams/index.ts:2120 wait for an entire idle Fast response instead of detaching it after admission.

_{Reviewed 2f6bb88}

[roomote-roomote]

Resolved the full admission/retry chain through f55540537, 0881bc25a, and 2f6bb8824. Durable storage precedes acknowledgement, Teams/Telegram release dedupe claims on failure and do not wait for inference, and queued turns use the message author's adapters. Focused API/SDK tests and pre-push gates pass. The previously failing Fresh-host Backup Restore rerun passed; its earlier Postgres health failure was transient and unrelated to this diff.