fix(12-04): add process signal handlers to ResourceCache

- Clear existing interval before creating new one in enablePersistence
- Register SIGTERM and SIGINT handlers for graceful shutdown
- Ensures intervals are cleaned up on process exit
- Prevents resource leaks in long-running processes

Author: kunwarVivek

src/infrastructure/cache/ResourceCache.ts

@@ -488,6 +488,12 @@ export class ResourceCache {
       return;
     }
 
+    // Clear any existing interval first to prevent duplicates
+    if (this.persistInterval) {
+      clearInterval(this.persistInterval);
+      this.persistInterval = undefined;
+    }
+
     this.persistence = new CachePersistence(cacheDirectory);
 
     // Start periodic persistence
@@ -500,6 +506,15 @@ export class ResourceCache {
       }
     }, this.PERSIST_INTERVAL_MS);
 
+    // Register cleanup on process termination signals
+    const cleanup = async () => {
+      await this.shutdown();
+      process.exit(0);
+    };
+
+    process.once('SIGTERM', cleanup);
+    process.once('SIGINT', cleanup);
+
     process.stderr.write(
       `[ResourceCache] Persistence enabled (interval: ${this.PERSIST_INTERVAL_MS}ms)\n`
     );