feat(core-storage): add PouchEnvelope tests and LocalStorageService implementation

- Introduced tests for PouchEnvelope to validate envelope-aware CRUD operations using an in-memory PouchDB.
- Implemented LocalStorageService with encryption support for sensitive keys, including tests for setItem, getItem, removeItem, and clear methods.
- Defined a generic storage interface (IStorageService) to enforce type-safe serialization/deserialization across storage implementations.

packages/core-storage/src/index.ts

@@ -1,10 +1,10 @@
 // ─── Interfaces ─────────────────────────────────────────────────
-export type { IStorageService } from './storage.interface';
-export type { StorageOptions } from './local-storage.service';
-export type { IndexedDBConfig } from './indexed-db.service';
-export type { PouchConfig } from './pouch';
+export type { IStorageService } from './types/storage.interface';
+export type { StorageOptions } from './local-storage/local-storage.service';
+export type { IndexedDBConfig } from './indexed-db/indexed-db.service';
+export type { PouchConfig, CouchEnvelope, FlatDoc, SyncStatus } from './pouch-db';
 
 // ─── Service Classes ────────────────────────────────────────────
-export { LocalStorageService, createLocalStorage } from './local-storage.service';
-export { IndexedDBService, createIndexedDB } from './indexed-db.service';
-export { PouchDatabaseManager, PouchDatabaseWrapper } from './pouch';
+export { LocalStorageService, createLocalStorage } from './local-storage/local-storage.service';
+export { IndexedDBService, createIndexedDB } from './indexed-db/indexed-db.service';
+export { PouchDBManager, PouchEnvelopeDBManager, PouchService, PouchEnvelopeService } from './pouch-db';