Dashboard web FastAPI + Chart.js

- 4 vues : spectre temps reel, historique detections, background, timeline CPS
- API REST : /api/status, /api/spectrum/current, /api/spectrum/difference,
  /api/background, /api/background/spectrum, /api/history, /api/cps/timeline
- Frontend vanilla JS + Chart.js (pas de Node.js, leger pour Pi 4)
- Moniteur modifie pour exporter son etat dans /data/monitor_state.json
  et le CPS dans /data/cps_log.jsonl chaque cycle
- Nouveau conteneur Docker 'web' sur port 8080
- Theme sombre, calibration energie (E = 0.33 + 2.97 * canal)

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

web/Dockerfile

@@ -0,0 +1,16 @@
+FROM python:3.11-slim
+
+ENV PYTHONUNBUFFERED=1
+ENV PYTHONDONTWRITEBYTECODE=1
+
+WORKDIR /app
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY app/ ./app/
+COPY static/ ./static/
+
+EXPOSE 8080
+
+CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8080", "--workers", "1"]