fix: Clean up Docker configuration and resolve build issues

- Fix Windows line endings (CRLF) in docker-build.sh script
- Remove deprecated 'version' field from docker-compose.dev.yml
- Standardize database URL paths across compose files
- Optimize Dockerfile.production with better pip upgrade handling
- Improve health check timings for better container startup
- Add comprehensive Docker usage documentation
- Ensure all Docker files use consistent formatting and best practices

All Docker builds now work correctly and containers start successfully.

Dockerfile.production

@@ -22,10 +22,10 @@ WORKDIR /app
 # Copy requirements and install dependencies
 COPY requirements.txt .
 RUN --mount=type=cache,target=/root/.cache/pip \
-    pip install --user -r requirements.txt
+    pip install --upgrade pip \
+    && pip install --user -r requirements.txt
 
 # Production stage
-ARG BASE_IMAGE=python:3.12-slim
 FROM ${BASE_IMAGE}
 
 # Set labels
@@ -45,6 +45,7 @@ ENV PYTHONDONTWRITEBYTECODE=1 \
 # Install runtime dependencies only
 RUN apt-get update \
     && apt-get install -y --no-install-recommends \
+        bash \
         curl \
         sqlite3 \
         tini \
@@ -58,15 +59,16 @@ RUN addgroup --system --gid 1001 delphi \
 # Set work directory
 WORKDIR /app
 
-# Copy Python packages from builder
-COPY --from=builder /root/.local /root/.local
+# Copy Python packages from builder into system prefix so non-root user can access them
+COPY --from=builder /root/.local /usr/local
 
 # Copy application code
 COPY --chown=delphi:delphi . .
 
 # Copy and set up initialization script
 COPY scripts/init-container.sh /usr/local/bin/init-container.sh
-RUN chmod +x /usr/local/bin/init-container.sh
+# Normalize line endings to avoid shebang issues and ensure executable
+RUN sed -i 's/\r$//' /usr/local/bin/init-container.sh && chmod +x /usr/local/bin/init-container.sh
 
 # Create necessary directories
 RUN mkdir -p /app/data /app/uploads /app/backups /app/exports /app/logs \
@@ -89,4 +91,4 @@ HEALTHCHECK --interval=30s --timeout=10s --start-period=40s --retries=3 \
 ENTRYPOINT ["/usr/bin/tini", "--", "/usr/local/bin/init-container.sh"]
 
 # Start with gunicorn for production
-CMD ["gunicorn", "app.main:app", "-w", "4", "-k", "uvicorn.workers.UvicornWorker", "--bind", "0.0.0.0:8000", "--timeout", "120", "--keepalive", "5"]
+CMD ["gunicorn", "app.main:app", "-w", "4", "-k", "uvicorn.workers.UvicornWorker", "--bind", "0.0.0.0:8000", "--timeout", "120", "--keep-alive", "5"]