refactor: extract memory host sdk package

tsconfig.plugin-sdk.dts.json

@@ -10,6 +10,10 @@
     "rootDir": ".",
     "tsBuildInfoFile": "dist/plugin-sdk/.tsbuildinfo"
   },
-  "include": ["src/plugin-sdk/**/*.ts", "src/types/**/*.d.ts"],
+  "include": [
+    "src/plugin-sdk/**/*.ts",
+    "src/types/**/*.d.ts",
+    "packages/memory-host-sdk/src/**/*.ts"
+  ],
   "exclude": ["node_modules", "dist", "src/**/*.test.ts"]
 }