Add API Support for Web/Backend Integration

#### Description
The current project is designed as a CLI tool for generating Preact components based on user-provided descriptions. However, it lacks an API that would allow it to be used in a web or backend environment. Adding an API would enable remote interaction with the generator, making it more versatile and easier to integrate with other systems.

#### Proposed Solution
Implement a RESTful API using a framework like FastAPI or Flask. The API should expose endpoints to:
1. Accept a component description and generate the corresponding files.
2. Optionally, handle additional configurations or variants.

#### Suggested Implementation
1. **Framework**: Use FastAPI for its modern features, speed, and built-in validation with Pydantic.
2. **Endpoints**:
- `POST /generate`: Accepts a JSON payload with the component description and returns the generated files.
3. **Integration**: Reuse the existing `ComponentGenerator` class to handle the generation logic.
4. **Output**: Return the generated files as part of the API response, including their paths and content.

#### Benefits
- Enables integration with web or mobile applications.
- Facilitates remote and automated usage of the generator.
- Provides a standardized interface for interacting with the tool.

#### Example API Design
```python
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel
from core.generator import ComponentGenerator
import os

app = FastAPI()

class ComponentRequest(BaseModel):
description: str

api_key = os.getenv("GEMINI_API_KEY")
if not api_key:
raise ValueError("❌ GEMINI_API_KEY not found in environment variables")

generator = ComponentGenerator(api_key=api_key, output_dir="./output/components")

@app.post("/generate")
def generate_component(request: ComponentRequest):
try:
files = generator.generate(request.description)
return {
"message": "Component generated successfully",
"files": [{"path": file.path, "content": file.content} for file in files],
}
except Exception as e:
raise HTTPException(status_code=500, detail=str(e))
```

#### Tasks
1. Choose a framework (FastAPI recommended).
2. Create a new file for the API (e.g., `api.py`).
3. Define the necessary endpoints.
4. Integrate the existing `ComponentGenerator` class.
5. Write tests for the API endpoints.

#### Additional Notes
- Ensure proper error handling and validation for the API.
- Provide documentation for the API, including example requests and responses.
- Consider adding CORS support if the API will be used in a browser-based frontend.

This enhancement will make the project more flexible and extend its usability beyond the CLI.