feat: Initialize test-ai-sdk project with Bun

- Add README.md with installation and usage instructions.
- Create bun.lock and pnpm-lock.yaml for dependency management.
- Implement main functionality in index.ts to test AI providers.
- Add opencode.json configuration for various AI providers.
- Create package.json to define project dependencies and scripts.
- Add TypeScript configuration in tsconfig.json for project setup.
- Implement test scripts for different AI providers in src directory.

AGENTS.md

@@ -0,0 +1,6 @@
+这是一个 bun 项目，测试 ai-sdk 功能。包是通过以下命令安装的：
+
+```bash
+bun add ai
+bun add @ai-sdk/openai
+```