Improve Dockerfile build configuration and layer caching

- Add SHELL pipefail to catch pipeline errors during build
   - Consolidate environment variables (PATH, PLAYWRIGHT_BROWSERS_PATH)
   - Fix DEBIAN_FRONTEND to inline usage (avoid runtime pollution)
   - Separate Playwright installation for better layer caching
   - Create dedicated /ms-playwright directory for browser binaries
   - Improve comments for better maintainability

   These changes enhance build robustness and optimize Docker layer
   caching without affecting runtime behavior.

Dockerfile

@@ -1,9 +1,13 @@
 FROM python:3.11-slim
 
-# Prevent Python from writing .pyc files and buffer stdout/stderr
+SHELL ["/bin/bash", "-o", "pipefail", "-c"]
+
+# Prevent Python from writing .pyc files, buffer stdout/stderr, and pin common tooling paths
 ENV PYTHONDONTWRITEBYTECODE=1 \
     PYTHONUNBUFFERED=1 \
-    PIP_NO_CACHE_DIR=1
+    PIP_NO_CACHE_DIR=1 \
+    PATH="/root/.local/bin:${PATH}" \
+    PLAYWRIGHT_BROWSERS_PATH=/ms-playwright
 
 # Install system dependencies required by scientific Python stack, Playwright, and Streamlit
 RUN apt-get update && apt-get install -y --no-install-recommends \
@@ -34,24 +38,24 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     ffmpeg \
     && apt-get clean && rm -rf /var/lib/apt/lists/*
 
-# Install uv and expose it on PATH
-ENV PATH="/root/.local/bin:${PATH}"
-RUN curl -LsSf https://astral.sh/uv/install.sh | sh
+# Install the latest uv release and expose it on PATH
+RUN curl -LsSf --retry 3 --retry-delay 2 https://astral.sh/uv/install.sh | sh
 
 WORKDIR /app
 
 # Install Python dependencies first to leverage Docker layer caching
-COPY requirements.txt ./ 
-RUN uv pip install --system -r requirements.txt && \
-    python -m playwright install chromium
+COPY requirements.txt ./
+RUN uv pip install --system -r requirements.txt
+
+# Install Playwright browser binaries (system deps already handled above)
+RUN python -m playwright install chromium
 
 # Copy application source
 COPY . .
 
 # Ensure runtime directories exist even if ignored in build context
-RUN mkdir -p logs final_reports insight_engine_streamlit_reports media_engine_streamlit_reports query_engine_streamlit_reports
+RUN mkdir -p /ms-playwright logs final_reports insight_engine_streamlit_reports media_engine_streamlit_reports query_engine_streamlit_reports
 
-# Expose Flask and Streamlit ports
 EXPOSE 5000 8501 8502 8503
 
 # Default command launches the Flask orchestrator which starts Streamlit agents