**Refactor:** Restructure server package to streamline imports and improve file organization

- Moved `providers`, `services`, `models`, `lib`, and related files to `src` directory within `server` package.
- Adjusted imports across the codebase to reflect the new paths.
- Renamed several `.ts` files for consistency.
- Introduced an `index.ts` in the `ai/providers` package to export all providers.

This improves maintainability and aligns with the project's updated directory structure.

packages/ai/providers/index.ts

@@ -0,0 +1,8 @@
+export * from './claude';
+export * from './cerebras';
+export * from './cloudflareAi';
+export * from './fireworks';
+export * from './groq';
+export * from './mlx-omni';
+export * from './ollama';
+export * from './xai';