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/app/routers/status.py

@@ -0,0 +1,40 @@
+import json
+from datetime import datetime
+from fastapi import APIRouter, HTTPException
+from app.config import STATE_PATH
+
+router = APIRouter()
+
+
+@router.get("/status")
+async def get_status():
+    """Current monitor status: connected, CPS, last isotopes detected."""
+    if not STATE_PATH.exists():
+        raise HTTPException(status_code=503, detail="Monitor not started yet")
+
+    try:
+        with open(STATE_PATH) as f:
+            state = json.load(f)
+    except (json.JSONDecodeError, OSError):
+        raise HTTPException(status_code=503, detail="Monitor state file corrupt")
+
+    # Check staleness (> 5 minutes old)
+    try:
+        ts = datetime.fromisoformat(state["timestamp"])
+        age = (datetime.now() - ts).total_seconds()
+        state["stale"] = age > 300
+        state["age_seconds"] = int(age)
+    except (KeyError, ValueError):
+        state["stale"] = True
+
+    return {
+        "connected": state.get("connected", False),
+        "stale": state.get("stale", True),
+        "age_seconds": state.get("age_seconds", 0),
+        "timestamp": state.get("timestamp", ""),
+        "cps": state.get("cps", 0),
+        "cumulated_live_time_h": state.get("cumulated_live_time_h", 0),
+        "total_counts": state.get("total_counts", 0),
+        "background_subtracted": state.get("background_subtracted", False),
+        "isotopes_detected": state.get("isotopes_detected", []),
+    }