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/core/src/db.ts

@@ -450,6 +450,14 @@ export class Database {
 
     // Future migrations go here:
     // if (version < 10) { this.applyMigration(10, () => { ... }); }
+
+    if (version < 10) {
+      this.applyMigration(10, () => {
+        this.addColumnIfMissing("missions", "autopilotEnabled", "INTEGER DEFAULT 0");
+        this.addColumnIfMissing("missions", "autopilotState", "TEXT DEFAULT 'inactive'");
+        this.addColumnIfMissing("missions", "lastAutopilotActivityAt", "TEXT");
+      });
+    }
   }
 
   /**