feat: initial dashboard implementation and robust attendance parsing

- Added a Makefile to easily run project scripts (fees, match, web, image)
- Modified attendance.py to dynamically handle a variable number of header rows from the Google Sheet
- Updated both attendance calculations and calculate_fees terminal output to show actual attendance counts (e.g., '750 CZK (3)')
- Created a Flask web dashboard (app.py and templates/fees.html) to view member fees in an attractive, condensed, terminal-like UI
- Bound the Flask server to port 5000 and added a routing alias from '/' to '/fees'
- Configured Python virtual environment (.venv) creation directly into the Makefile to resolve global pip install errors on macOS

Co-authored-by: Antigravity <antigravity@deepmind.com>

build/Dockerfile

@@ -0,0 +1,25 @@
+FROM python:3.13-alpine
+
+RUN apk add --no-cache bash tzdata \
+    && cp /usr/share/zoneinfo/Europe/Prague /etc/localtime \
+    && echo "Europe/Prague" > /etc/timezone
+
+ENV PYTHONUNBUFFERED=1
+
+WORKDIR /app
+
+RUN pip install --no-cache-dir flask
+
+COPY app.py Makefile ./
+COPY scripts/ ./scripts/
+COPY templates/ ./templates/
+
+COPY build/entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+EXPOSE 5001
+
+HEALTHCHECK --interval=60s --timeout=5s --start-period=5s \
+    CMD wget -q -O /dev/null http://localhost:5001/ || exit 1
+
+ENTRYPOINT ["/entrypoint.sh"]