feat(core): init @openchatlab/core package with abstract interfaces

Phase 1.1 of CLI/Web transformation: create the platform-agnostic core
package with DatabaseAdapter, PathProvider, NotificationBus interfaces
and query filter utilities extracted from worker/core/dbCore.ts.

tsconfig.node.json

@@ -7,7 +7,8 @@
     "electron/preload/**/*",
     "electron/shared/**/*",
     "src/types/**/*",
-    "packages/shared-types/**/*"
+    "packages/shared-types/**/*",
+    "packages/core/**/*"
   ],
   "compilerOptions": {
     "composite": true,