Dash web: crosshair, zoom/pan X, scale log/lin, continuum extraction, background resume

- Tooltip entier (intersect:false) + ligne verticale crosshair sur tous les graphes
- Zoom molette/pinch sur l'axe X, pan souris, limites clamped 30-3000 keV
- Toggle échelle log/linéaire onglet Background
- Extraction continuum détecteur (isotope peaks subtracted + Gaussian smoothing)
- Reprise snapshot précédent au démarrage capture_background.py
- Suppression refs "Théorique" et "Bruit capteur" de l'interface
- Plugin chartjs-plugin-zoom + hammerjs via CDN
- Fix Chart constructor spread operator

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web/static/js/cps.js

@@ -44,8 +44,36 @@ function updateCpsChart(labels, values) {
     const options = {
         responsive: true,
         maintainAspectRatio: false,
+        interaction: { mode: 'index', intersect: false },
         plugins: {
             legend: { labels: { color: '#e0e0e0' } },
+            tooltip: {
+                enabled: true,
+                mode: 'index',
+                intersect: false,
+                filter: (item) => item.raw != null,
+                callbacks: {
+                    title: (items) => {
+                        const d = new Date(items[0].parsed.x / 1000);
+                        return d.toLocaleString('fr-FR', { day: '2-digit', month: '2-digit', hour: '2-digit', minute: '2-digit' });
+                    },
+                    label: (item) => `${item.dataset.label}: ${item.raw.toFixed(2)}`
+                }
+            },
+            zoom: {
+                pan: {
+                    enabled: true,
+                    mode: 'x',
+                    modifierKey: null,
+                },
+                zoom: {
+                    wheel: { enabled: true },
+                    pinch: { enabled: true },
+                    drag: { enabled: false },
+                    mode: 'x',
+                    onZoom: () => { document.getElementById('reset-zoom-cps').style.display = 'inline-block'; }
+                }
+            }
         },
         scales: {
             x: {
@@ -76,8 +104,16 @@ function updateCpsChart(labels, values) {
         const script = document.createElement('script');
         script.src = 'https://cdn.jsdelivr.net/npm/chartjs-adapter-date-fns@3.0.0/dist/chartjs-adapter-date-fns.bundle.min.js';
         script.onload = () => {
-            cpsChart = new Chart(ctx, { type: 'line', data: chartData, options });
+            cpsChart = new Chart(ctx, { type: 'line', data: chartData, ...options });
         };
         document.head.appendChild(script);
     }
-}
+}
+
+// Reset zoom
+document.getElementById('reset-zoom-cps')?.addEventListener('click', () => {
+    if (cpsChart) {
+        cpsChart.resetZoom();
+        document.getElementById('reset-zoom-cps').style.display = 'none';
+    }
+});