Refactor Dockerfile to streamline build process and remove frontend build stage

- Removed the multi-stage build for frontend assets, simplifying the Dockerfile.
- Consolidated application code copying to include the static frontend directory directly.
- Updated comments for clarity on the changes made to the build process.

Dockerfile

@@ -1,21 +1,3 @@
-# Stage 1: Build frontend assets
-FROM node:20-slim AS frontend-builder
-
-WORKDIR /app/frontend
-
-# Copy frontend package files
-COPY frontend/package*.json ./
-
-# Install dependencies
-RUN npm ci
-
-# Copy frontend source
-COPY frontend/ ./
-
-# Build frontend
-RUN npm run build
-
-# Stage 2: Python runtime
 FROM python:3.11-slim-bookworm
 
 # Install system dependencies for MuJoCo and OpenCV
@@ -42,12 +24,9 @@ COPY requirements.txt .
 # Install Python dependencies
 RUN pip install --no-cache-dir -r requirements.txt
 
-# Copy application code
+# Copy application code (including the static frontend directory)
 COPY . .
 
-# Copy built frontend assets from builder stage
-COPY --from=frontend-builder /app/frontend/dist ./frontend/dist
-
 # Environment variables for headless rendering
 # Options: osmesa (software, slow), egl (GPU if available), glx (X11 GPU)
 ENV MUJOCO_GL=osmesa