[NA] [BE] First build of Local Runner backend

[collincunn]

Details

The Local Runner feature allows users to execute AI agents on their own machines, triggered from the Opik UI.

• Implemented the full backend for the Local Runner feature (zero SDK yet)
• Added REST API under /v1/private/runners with endpoints for pairing, connection, job lifecycle, log streaming, heartbeat, and cancellation
• Implemented RunnerServiceImpl with all Redis-backed state management (runner state, job queues, agent registry, heartbeat liveness)
• Added RunnerReaperJob for periodic cleanup of dead runners and orphaned job recovery
• Added RunnerConfig for feature gating and tunable parameters (job timeout, queue depth, heartbeat TTL)
• Included comprehensive unit tests covering pairing, connection, job creation/execution/cancellation, log streaming, heartbeat/eviction, reaper logic, and workspace isolation

Change checklist

• User facing
• Documentation update

Testing

• Created ~80 unit tests that cover 100% of the runner service.
• Created an integration test that runs against Redis

Issues

Documentation

See design doc

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Backend Tests Results

  452 files    452 suites   56m 33s ⏱️
6 945 tests 6 932 ✅ 13 💤 0 ❌
5 476 runs  5 463 ✅ 13 💤 0 ❌

Results for commit 6873c55.

♻️ This comment has been updated with latest results.