[Feat] Add durable task acknowledgement lifecycle

[roomote-community]

​Opened on behalf of @mrubens. Follow up by mentioning @roomote, in the web UI, or in Discord.

What changed

• Added a durable acknowledgement lifecycle for plan and implementation deliverables without changing runtime task state.
• Keeps completed deliverables in Needs input until they are marked done or every linked pull request merges, while question tasks can finish directly in Done.
• Clears prior acknowledgement state when follow-up work starts and handles linked pull request outcomes consistently across supported source-control providers.
• Added Mark done actions to task-board cards and task details, with board placement for awaiting, acknowledged, and closed-unmerged results.

Why this change was made

Deliverables could previously disappear into completed work as soon as execution became idle, even when a person still needed to review or accept the result. A separate durable resolution state keeps runtime truth intact while making that review lifecycle explicit and race-safe.

Impact

People can now see which plans and implementations are awaiting acceptance, explicitly mark them done, and rely on merged pull requests to acknowledge linked work automatically. Concurrent follow-ups and out-of-order pull request events cannot incorrectly hide active or unresolved work.

[roomote-community]

No new code issues found. See task

• apps/web/src/components/tasks/TaskBoard.tsx:71 reports success when acknowledgement did not change the task state.
• apps/api/src/handlers/tasks/sendMessageToTask.ts:1040 leaves web-composer follow-ups outside the resolution-clearing path.

_{Reviewed 999cd58}

[roomote-community]

Fixed both review findings in 0163ac7: acknowledgement UI now reports success only when persistence changes, and web-composer follow-ups clear the prior resolution before sandbox delivery. Added regression coverage for both paths; targeted tests, web lint, type checking, and pre-push checks pass.