Firecrawl API Returns "Bad Request" Error Due to Invalid URL in `/api/scrape-screenshot` Route

### Firecrawl API Returns "Bad Request" Error Due to Invalid URL in `/api/scrape-screenshot` Route

#### Description
When running the Open Lovable app locally after setup, attempting to use the screenshot/scrape functionality results in a 500 error from the `/api/scrape-screenshot` endpoint. The error indicates a "Bad Request" from the Firecrawl API, specifically complaining about an invalid URL (missing valid top-level domain or invalid path).

This seems to occur because the URL being passed to Firecrawl is not a valid, publicly accessible one—possibly a local URL like `http://localhost:3000` or an improperly formed E2B sandbox URL.

#### Steps to Reproduce
1. Clone the repo: `git clone https://github.com/mendableai/open-lovable.git`
2. Install dependencies: `cd open-lovable && npm install`
3. Create `.env.local` with required keys:
```
E2B_API_KEY=your_e2b_key # Obtained from https://e2b.dev
FIRECRAWL_API_KEY=your_firecrawl_key # Obtained from https://firecrawl.dev
# Optional AI key, e.g., ANTHROPIC_API_KEY=your_anthropic_key
```
4. Run the app: `npm run dev`
5. Open http://localhost:3000 and interact with the chat to build a React app (which triggers the scrape/screenshot).
6. Observe the error in the console/server logs:
```
Error: Firecrawl API error: {"success":false,"error":"Bad Request","details":[{"validation":"url","code":"invalid_string","message":"Invalid url","path":["url"]},{"code":"custom","message":"URL must have a valid top-level domain or be a valid path","path":["url"]},{"code":"custom","message":"Invalid URL","path":["url"]}]}
at POST (app/api/scrape-screenshot/route.ts:35:12)
POST /api/scrape-screenshot 500 in 567ms
```

#### Expected Behavior
The app should successfully scrape/screenshot the generated React app preview (likely from an E2B sandbox) without Firecrawl errors.

#### Actual Behavior
Firecrawl rejects the request with a "Bad Request" due to an invalid URL.

#### Additional Details
- **Environment**:
- Node.js version: v23.9.0
- OS: macOS 15.3.2 (24D81)
- Browser: Brave 1.80.125
Chromium: 138.0.7204.184
- **Troubleshooting Tried**:
- Verified Firecrawl API key works directly via curl:
```
curl -X POST https://api.firecrawl.dev/v0/scrape \
-H "Authorization: Bearer fc-XXXX" \
-H "Content-Type: application/json" \
-d '{"url": "https://www.google.com"}'
```
This returns a successful response with scraped content.
- Added logging to `app/api/scrape-screenshot/route.ts` to check the URL being sent – it appears to be invalid (e.g., local or malformed).
- Ensured E2B_API_KEY is set, as it's required for generating sandbox previews.
- **Possible Causes**:
- The URL generated for the preview (e.g., from E2B sandbox) might not be fully qualified or publicly accessible.
- If E2B sandbox fails to initialize, it could fallback to a local URL, which Firecrawl can't access.
- Lack of validation in the route for the URL before sending to Firecrawl.

#### Suggested Fix
- Add URL validation in `app/api/scrape-screenshot/route.ts` before the Firecrawl fetch (e.g., using `valid-url` package).
- Ensure the preview URL is always a public E2B sandbox URL; if local, perhaps integrate a tunneling service like ngrok for development.
- Hardcode a test URL in the route temporarily to confirm it works with valid inputs.

This blocks local development for new users. Happy to provide more logs or test patches!