semi implemented and features implemented save checkpoint

docs/features/unchecked/orchestrator/job-lifecycle-state-machine.md

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+# Job Lifecycle State Machine
+
+## Module
+Orchestrator
+
+## Status
+IMPLEMENTED
+
+## Description
+Job scheduling with Postgres-backed job repository, event envelope domain model, and air-gap compatible scheduling tests.
+
+## Implementation Details
+- **Modules**: `src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Core/Scheduling/`, `src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Core/Domain/`
+- **Key Classes**:
+  - `JobStateMachine` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Core/Scheduling/JobStateMachine.cs`) - finite state machine governing job lifecycle transitions (Pending -> Scheduled -> Running -> Completed/Failed/Cancelled)
+  - `JobScheduler` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Core/Scheduling/JobScheduler.cs`) - schedules jobs based on state machine rules and DAG dependencies
+  - `RetryPolicy` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Core/Scheduling/RetryPolicy.cs`) - configurable retry policy for failed jobs (max retries, backoff strategy)
+  - `Job` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Core/Domain/Job.cs`) - job entity with current status, attempts, and metadata
+  - `JobStatus` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Core/Domain/JobStatus.cs`) - enum defining all valid job states
+  - `JobHistory` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Core/Domain/JobHistory.cs`) - historical record of all state transitions with timestamps
+  - `EventEnvelope` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Core/Domain/Events/EventEnvelope.cs`) - typed event envelope emitted on state transitions
+  - `TimelineEvent` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Core/Domain/Events/TimelineEvent.cs`) - timeline event for job lifecycle tracking
+  - `TimelineEventEmitter` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Core/Domain/Events/TimelineEventEmitter.cs`) - emits timeline events on state transitions
+  - `JobEndpoints` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.WebService/Endpoints/JobEndpoints.cs`) - REST API for job management
+  - `JobContracts` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.WebService/Contracts/JobContracts.cs`) - API contracts for job operations
+- **Interfaces**: `IJobRepository` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Infrastructure/Repositories/IJobRepository.cs`), `IJobHistoryRepository` (`src/Orchestrator/StellaOps.Orchestrator/StellaOps.Orchestrator.Infrastructure/Repositories/IJobHistoryRepository.cs`)
+- **Source**: Feature matrix scan
+
+## E2E Test Plan
+- [ ] Create a job via `JobEndpoints` and verify initial state is Pending
+- [ ] Schedule the job via `JobScheduler` and verify state transition: Pending -> Scheduled, with `TimelineEvent` emitted
+- [ ] Start the job and verify `JobStateMachine` transition: Scheduled -> Running
+- [ ] Complete the job and verify transition: Running -> Completed with completion timestamp in `JobHistory`
+- [ ] Fail the job and verify transition: Running -> Failed with retry attempt incremented
+- [ ] Verify `RetryPolicy`: fail a job with max_retries=3 and verify it re-enters Scheduled up to 3 times before terminal failure
+- [ ] Attempt an invalid transition (e.g., Completed -> Running) and verify `JobStateMachine` rejects it
+- [ ] Verify air-gap scheduling: schedule a job in sealed mode and verify it does not attempt network egress