fix(docker): bind Next to 7860 and expose 7860 for HF Spaces health checks

Dockerfile

@@ -14,13 +14,13 @@ COPY --chown=1000 . .
 # Build the app
 RUN npm run build
 
-# Expose default Next.js port (informational)
-EXPOSE 3000
+# Expose the port expected by Hugging Face Docker Spaces
+EXPOSE 7860
 
 # HF Spaces provides $PORT. Start Next.js on that port and bind to all interfaces.
 ENV HOST=0.0.0.0
 # Disable telemetry and ensure production env
 ENV NEXT_TELEMETRY_DISABLED=1
 ENV NODE_ENV=production
-# Run Next directly to avoid npm CLI usage output if args aren't forwarded
-CMD ["sh", "-c", "node node_modules/next/dist/bin/next start -H 0.0.0.0 -p ${PORT:-3000}"]
+# Run Next directly on the fixed port used by Spaces
+CMD ["sh", "-c", "node node_modules/next/dist/bin/next start -H 0.0.0.0 -p 7860"]