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.

.gitignore

@@ -0,0 +1,36 @@
+# dependencies (bun install)
+node_modules
+
+# output
+out
+dist
+*.tgz
+
+# code coverage
+coverage
+*.lcov
+
+# logs
+logs
+_.log
+report.[0-9]_.[0-9]_.[0-9]_.[0-9]_.json
+
+# dotenv environment variable files
+.env
+.env.development.local
+.env.test.local
+.env.production.local
+.env.local
+
+# caches
+.eslintcache
+.cache
+*.tsbuildinfo
+
+# IntelliJ based IDEs
+.idea
+
+# Finder (MacOS) folder config
+.DS_Store
+
+!.env*example