feat(cache): add persistent smartdata-backed cache with LocalTsmDb, cache cleaner, and DcRouter integration

ts/cache/classes.cached.document.ts

@@ -7,24 +7,27 @@ import * as plugins from '../plugins.js';
  * - Automatic timestamps (createdAt, lastAccessedAt)
  * - TTL/expiration support (expiresAt)
  * - Helper methods for TTL management
+ *
+ * NOTE: Subclasses MUST add @svDb() decorators to createdAt, expiresAt, and lastAccessedAt
+ * since decorators on abstract classes don't propagate correctly.
  */
 export abstract class CachedDocument<T extends CachedDocument<T>> extends plugins.smartdata.SmartDataDbDoc<T, T> {
   /**
    * Timestamp when the document was created
+   * NOTE: Subclasses must add @svDb() decorator
    */
-  @plugins.smartdata.svDb()
   public createdAt: Date = new Date();
 
   /**
    * Timestamp when the document expires and should be cleaned up
+   * NOTE: Subclasses must add @svDb() decorator
    */
-  @plugins.smartdata.svDb()
   public expiresAt: Date;
 
   /**
    * Timestamp of last access (for LRU-style eviction if needed)
+   * NOTE: Subclasses must add @svDb() decorator
    */
-  @plugins.smartdata.svDb()
   public lastAccessedAt: Date = new Date();
 
   /**