chore: update package.json and add tsdown configuration for build process

- Changed the main and types entries in package.json to point to the dist directory for better output management.
- Added a new tsdown.config.ts file to define the build configuration, specifying entry points, output directory, and formats for the project.

packages/aiCore/package.json

@@ -2,8 +2,8 @@
   "name": "@cherrystudio/ai-core",
   "version": "1.0.0",
   "description": "Cherry Studio AI Core - Unified AI Provider Interface Based on Vercel AI SDK",
-  "main": "src/index.ts",
-  "types": "src/index.ts",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
   "scripts": {
     "build": "tsdown",
     "dev": "tsc -w",
@@ -125,14 +125,14 @@
   ],
   "exports": {
     ".": {
-      "types": "./src/index.ts",
-      "import": "./src/index.ts",
-      "require": "./src/index.ts"
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.mjs",
+      "require": "./dist/index.js"
     },
     "./core/plugins/built-in": {
-      "types": "./src/core/plugins/built-in/index.ts",
-      "import": "./src/core/plugins/built-in/index.ts",
-      "require": "./src/core/plugins/built-in/index.ts"
+      "types": "./dist/core/plugins/built-in/index.d.ts",
+      "import": "./dist/core/plugins/built-in/index.mjs",
+      "require": "./dist/core/plugins/built-in/index.js"
     }
   }
 }

packages/aiCore/tsdown.config.ts

@@ -0,0 +1,13 @@
+import { defineConfig } from 'tsdown'
+
+export default defineConfig({
+  entry: {
+    index: 'src/index.ts',
+    'core/plugins/built-in/index': 'src/core/plugins/built-in/index.ts'
+  },
+  outDir: 'dist',
+  format: ['esm', 'cjs'],
+  clean: true,
+  dts: true,
+  tsconfig: 'tsconfig.json'
+})