Tasks: Return log snapshot from logs endpoint when paused #1254

Repo: coder/coder

Scope: Modify task logs endpoint to return stored snapshot when task is paused.

Changes:

• Modify GET /api/v2/tasks/{user}/{task}/logs in coderd/aitasks.go
• Check workspace status first
• If task is active: fetch live logs from AgentAPI and return normalized logs (existing behavior)
• If task is paused:
  • query task_snapshots
  • decode stored wrapper {"format":"agentapi","data":...}
  • normalize decoded AgentAPI payload into the same log entry schema used for live logs
  • add snapshot: true and snapshot_at
• Add snapshot (bool), snapshot_at (timestamp), total_count (int) fields to response

Files:

• coderd/aitasks.go
• codersdk/aitasks.go

Acceptance criteria:

• Live logs returned when workspace running
• Stored snapshot returned when task is paused
• Response includes snapshot: true and snapshot_at when returning snapshot
• Returns empty logs response when no snapshot available
• total_count equals the number of messages returned in the response

Dependencies:

• Tasks: Database migrations for task lifecycle #1250
• Tasks: Log snapshot storage endpoint #1253

References:

• PRD: Start/Pause/Resume the Task Workspace
• RFC: Tasks: Start/Pause/Resume Lifecycle: API Changes (Modified endpoints)