feat: port 4 valuable PRs from YOUTUBE-EXTENSION (pre-archive salvage)

Dockerfile.cloudrun

@@ -0,0 +1,60 @@
+# Cloud Run Optimized Dockerfile
+# Uses Python 3.11 slim with multi-stage build for smaller image size
+
+FROM python:3.11-slim as builder
+
+# Install build dependencies
+RUN apt-get update && apt-get install -y \
+    gcc \
+    g++ \
+    make \
+    && rm -rf /var/lib/apt/lists/*
+
+# Set working directory
+WORKDIR /app
+
+# Copy dependency files
+COPY pyproject.toml README.md ./
+COPY src/ src/
+
+# Install dependencies with cloud extras
+RUN pip install --no-cache-dir --user -e .[youtube,ml,cloud,postgres]
+
+# Production stage
+FROM python:3.11-slim
+
+# Install runtime dependencies
+RUN apt-get update && apt-get install -y \
+    libgomp1 \
+    && rm -rf /var/lib/apt/lists/*
+
+# Create non-root user
+RUN useradd -m -u 1000 appuser
+
+# Set working directory
+WORKDIR /app
+
+# Copy installed packages from builder
+COPY --from=builder /root/.local /home/appuser/.local
+COPY --from=builder /app /app
+
+# Set ownership
+RUN chown -R appuser:appuser /app
+
+# Switch to non-root user
+USER appuser
+
+# Add local packages to PATH
+ENV PATH=/home/appuser/.local/bin:$PATH
+ENV PYTHONPATH=/app/src:$PYTHONPATH
+
+# Expose port
+EXPOSE 8000
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
+    CMD python -c "import requests; requests.get('http://localhost:8000/health', timeout=5)"
+
+# Run application with uvicorn
+# Cloud Run manages scaling, so we use 1 worker
+CMD ["uvicorn", "youtube_extension.main:app", "--host", "0.0.0.0", "--port", "8000", "--workers", "1"]