feat(FN-4401): complete Step 1 — add auto-claim snapshot manager

Fusion-Task-Id: FN-4401
Fusion-Task-Lineage: c1b6c497-b22c-48d5-b1c8-299877bf09ac

packages/core/src/types.ts

@@ -4663,6 +4663,8 @@ export interface AgentHeartbeatConfig {
   enabled?: boolean;
   /** Whether this agent should auto-claim relevant unowned tasks during no-task heartbeats (default: true when unset). */
   autoClaimRelevantTasks?: boolean;
+  /** Number of auto-claim candidates to inject into no-task heartbeat prompts. Default: 5, range: 0-10. */
+  autoClaimCandidatesInPrompt?: number;
   /** Polling interval in ms (default: 30000). Min: 1000 */
   heartbeatIntervalMs?: number;
   /** Heartbeat timeout in ms (default: 60000). Min: 5000 */