Fix Docker deployment and runtime environment variables

- Add --break-system-packages flag to pip install for Alpine Linux 3.12+ compatibility
- Configure Astro server to bind to 0.0.0.0 for Docker container accessibility
- Replace import.meta.env with process.env for runtime environment variable access in SSR
- Enable dynamic LOGIN configuration at runtime

Co-Authored-By: Warp <agent@warp.dev>

src/pages/api/download-file.ts

@@ -25,7 +25,7 @@ export const GET: APIRoute = async ({ request }) => {
 
     // Download-Verzeichnis aus Environment-Variable
     const downloadDir =
-      import.meta.env.DOWNLOAD_DIR || path.join(process.cwd(), "downloaded");
+      process.env.DOWNLOAD_DIR || path.join(process.cwd(), "downloaded");
 
     const filePath = path.join(downloadDir, fileName);