fix(runtime): ensure /data is writable for non-root (chmod -R 777 /data)

Dockerfile

@@ -25,7 +25,7 @@ COPY . .
 
 # Create directories for uploads and results
 # Ensure writable data directory exists for Spaces
-RUN mkdir -p /data/uploads /data/results && chown -R 1000:1000 /data
+RUN mkdir -p /data/uploads /data/results && chmod -R 777 /data
 
 # Handle Firebase credentials from environment variable (for Hugging Face Spaces secrets)
 # This allows the credentials to be passed as a secret and written to file at runtime