feat: refactor to SI Quiz with Space Invaders arcade interface

- Updated Dockerfile to Python 3.11, selective COPY for cleaner image
- Expanded .gitignore with Python/OS patterns
- Added config.json, questions.json, env_example, and static assets
- Updated templates (host, player, scores) with Space Invaders UI
- Rewrote README for SI Quiz branding and setup docs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -1,7 +1,16 @@
-FROM python:3.12-slim
+FROM python:3.11-slim
+
 WORKDIR /app
+
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
-COPY . .
+
+COPY main.py .
+COPY config.json .
+COPY questions.json .
+COPY templates/ templates/
+COPY static/ static/
+
 EXPOSE 8000
-CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]
+
+CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]