feat(FN-3323): recover orphaned agents and add reports health section to he

The merge lands FN-3323's self-healing system: a new "reports health" prompt section and `agent-heartbeat.ts` module that detect orphaned agents and recover their state (clearing stale error states and re-enabling heartbeat execution). The engine's `self-healing.ts` was expanded with wired recovery

Fusion-Task-Id: FN-3323

packages/engine/src/runtimes/in-process-runtime.ts

@@ -668,6 +668,7 @@ export class InProcessRuntime
       // 7. Initialize SelfHealingManager
       this.selfHealingManager = new SelfHealingManager(this.taskStore, {
         rootDir: this.config.workingDirectory,
+        agentStore: this.agentStore,
         recoverCompletedTask: (task) => this.executor.recoverCompletedTask(task),
         recoverFailedPreMergeStep: (task) => this.executor.recoverFailedPreMergeWorkflowStep(task),
         getExecutingTaskIds: () => this.executor.getExecutingTaskIds(),