feat(FN-980): add mission autopilot for autonomous slice progression

- Add MissionAutopilot class with state machine (inactive → watching → activating → completing)
- Add autopilot database schema: autopilotEnabled, autopilotState, lastAutopilotActivityAt columns
- Integrate autopilot with scheduler: handleTaskCompletion() triggers slice activation
- Add API routes: GET/PATCH /missions/:id/autopilot, POST start/stop endpoints
- Add autopilot toggle UI in MissionManager dashboard component
- Add retry logic with exponential backoff (up to 3 attempts) for slice activation
- Add background poll (60s) to detect stale autopilot missions
- Include changeset for @gsxdsm/fusion minor bump

packages/engine/src/index.ts

@@ -3,6 +3,7 @@ export { AgentSemaphore, PRIORITY_MERGE, PRIORITY_EXECUTE, PRIORITY_SPECIFY } fr
 export { TriageProcessor, type TriageProcessorOptions } from "./triage.js";
 export { TaskExecutor, type TaskExecutorOptions } from "./executor.js";
 export { Scheduler, type SchedulerOptions } from "./scheduler.js";
+export { MissionAutopilot, type MissionAutopilotOptions } from "./mission-autopilot.js";
 export { aiMergeTask, type MergerOptions } from "./merger.js";
 export { reviewStep, type ReviewType, type ReviewVerdict, type ReviewResult, type ReviewOptions } from "./reviewer.js";
 export { createKbAgent, type AgentOptions, type AgentResult } from "./pi.js";