## 1. Job Contracts

- [x] 1.1 Add typed run job protocol payloads in `run/protocol` for claim, ack, progress, result, cancel polling, and reconcile.
- [x] 1.2 Add matching platform DTO/domain contracts and conversion helpers for job-channel requests and responses.
- [x] 1.3 Add validation rules for bounded job payloads, lifecycle states, progress, session, lease, and terminal result metadata.

## 2. Platform Job Channel

- [x] 2.1 Extend platform service behavior for job claim leasing, session checks, ack, progress, terminal results, cancellation, reconcile, and idempotency.
- [x] 2.2 Implement platform job-channel HTTP routes using named DTOs and service methods.
- [x] 2.3 Add platform service/API tests for lifecycle success, no-job claim, invalid session/lease, invalid progress, cancellation, duplicate results, conflicting results, and reconcile.

## 3. Run Job Client

- [x] 3.1 Extend `run/api.PlatformClient` with typed job claim, ack, progress, result, cancel polling, and reconcile methods.
- [x] 3.2 Add run client tests for request paths, JSON payloads, response decoding, and platform error handling.
- [x] 3.3 Add an integration-style client test that claims a job, acknowledges it, reports progress, submits a result, and reconciles against a test platform job endpoint.

## 4. Documentation

- [x] 4.1 Update run and platform protocol/route documentation to mark job-channel endpoints implemented and keep log/artifact/game-client channels separate.

## 5. Verification

- [x] 5.1 Run `go test ./...` from `platform/` and record evidence.
- [x] 5.2 Run `go test ./...` from `run/` and record evidence.
- [x] 5.3 Run `scripts/check-structure.sh` and record evidence.
- [x] 5.4 Run `openspec validate implement-run-job-channel --strict` and record evidence.

## Evidence

- 2026-07-03: `go test ./...` from `platform/` passed.
- 2026-07-03: `go test ./...` from `run/` passed.
- 2026-07-03: `scripts/check-structure.sh` passed with `structure check passed`.
- 2026-07-03: `openspec validate implement-run-job-channel --strict` passed with `Change 'implement-run-job-channel' is valid`.