feat: discharge-driven river animation speed, replay stat tiles, hourly doc render

- river dash animation now flows at a speed continuously derived from
  each segment's discharge (period 260/(Q+45) s, clamped 0.5-5.5 s) via
  inline per-path animation-duration, so it updates live and per-frame
  during the replay (CSS speed classes removed - setStyle cannot change
  classes)
- the replay drives the Combined discharge and Strongest flow stat
  tiles each frame (marked '2024 replay'), restored on finish
- docs: hour-by-hour detection detail render (22-28 Sep 2024) showing
  the model alert at 24 Sep 01:00, flooding at 25 Sep 01:00, and the
  24 h warning between them; embedded with commentary
- Matrix alerts now link to https://water.buildfor.life/ (override via
  ALERT_DASHBOARD_URL), replacing the Grafana public dashboard link

docs/FLOOD_FORECASTING.md

@@ -306,6 +306,16 @@ honestly: the predicted peak tops out ~0.4 m short of the actual 5.30 m record
 noisier on the recession limbs. The same model track drives the dashboard's
 "Replay Oct 2024 flood" feature, so this chart can be watched live on the map.
 
+![Hour-by-hour detail of the detection window, 22–28 September
+2024](img/backtest-2024-p1-detail.png)
+
+The hour-by-hour detail of the detection window shows the sequence exactly: the
+predicted 24 h peak (amber) starts pulling away from the observed level late on
+23 September as upstream gauges rise, the warning probability snaps from ~0 to
+1.0 at **01:00 on 24 September**, and the river crosses 3.70 m at **01:00 on
+25 September** — a clean 24-hour warning, delivered while the river in town
+still looked normal at 2.8 m.
+
 - **25 September cold start.** P.1's first warning crossing of the episode was
   alerted **24–26 hours ahead**. This is the genuinely impressive case: the river
   was in normal state, and the alert came from upstream routing alone.

src/alerting.py

@@ -155,9 +155,9 @@ class MatrixNotifier:
         if alert.message:
             message += f"\n**Details:** {alert.message}\n"
 
-        # Add Grafana public dashboard link
+        # Add live dashboard link
-        grafana_url = "https://metrics.b4l.co.th/public-dashboards/655730aa044f44f49b355d01386018ca"
+        dashboard_url = os.getenv("ALERT_DASHBOARD_URL", "https://water.buildfor.life/")
-        message += f"\n📈 **View Dashboard:** {grafana_url}"
+        message += f"\n📈 **View Dashboard:** {dashboard_url}"
 
         return self.send_message(message)
 

src/static/dashboard.html

@@ -116,12 +116,7 @@
             opacity: .36; animation: pulse 2.2s ease-out infinite;
         }
         @keyframes pulse { 0% { transform: scale(.72); opacity: .55; } 75%,100% { transform: scale(1.35); opacity: 0; } }
-        .flow-line { animation: riverMove 3s linear infinite; }
+        .flow-line { animation: riverMove 3s linear infinite; } /* per-segment duration set inline from discharge */
-        .flow-idle { animation-duration: 5.5s; }
-        .flow-slow { animation-duration: 3s; }
-        .flow-med { animation-duration: 1.9s; }
-        .flow-fast { animation-duration: 1.15s; }
-        .flow-surge { animation-duration: .7s; }
         @keyframes riverMove { to { stroke-dashoffset: -40; } }
         @media (prefers-reduced-motion: reduce) { .flow-line, .flow-marker::before { animation: none; } }
         .line-swatch { width: 24px; height: 4px; border-radius: 2px; flex: none; }
@@ -353,12 +348,18 @@
         return q == null ? 2.5 : Math.max(3, Math.min(9, 2.5 + Math.sqrt(Math.max(0, q)) * .38));
     }
 
-    function riverSpeedClass(q) {
+    // Continuous dash-animation period from discharge: calm water drifts (~5.5 s
-        if (q == null) return 'flow-idle';
+    // per cycle), a flood races (~0.5 s). Applied as inline animation-duration on
-        if (q < 25) return 'flow-slow';
+    // each SVG path so it can be updated live (setStyle cannot change classes).
-        if (q < 100) return 'flow-med';
+    function flowDuration(q) {
-        if (q < 250) return 'flow-fast';
+        if (q == null) return 5.5;
-        return 'flow-surge';
+        return Math.max(.5, Math.min(5.5, 260 / (Number(q) + 45)));
+    }
+
+    function applyFlowSpeed(layerGroup, flows) {
+        layerGroup.eachLayer((layer) => {
+            if (layer._path) layer._path.style.animationDuration = `${flowDuration(flows.get(layer.feature))}s`;
+        });
     }
 
     function riverGauges(stations, readings) {
@@ -387,12 +388,13 @@
                 return {
                     color: q == null ? '#69b7d0' : flowColor(q),
                     weight: riverWeight(q), opacity: .92, lineCap: 'round',
-                    dashArray: '6 14', className: `flow-line ${riverSpeedClass(q)}`
+                    dashArray: '6 14', className: 'flow-line'
                 };
             }
         }).addTo(state.map);
         flow.bringToBack();
         casing.bringToBack();
+        applyFlowSpeed(flow, flowBySegment);
         state.layers.push(casing, flow);
         state.riverNet = riverNetwork;
         state.riverStations = stations;
@@ -410,6 +412,7 @@
             const q = flows.get(f);
             return { color: q == null ? '#69b7d0' : flowColor(q), weight: riverWeight(q), opacity: .92 };
         });
+        applyFlowSpeed(state.riverFlow, flows);
     }
 
     function updateStationMarker(code, discharge) {
@@ -820,13 +823,21 @@
                 const frame = Math.min(i, n - 1);
                 const readings = new Map();
                 let totalFlow = 0;
+                let peakFlow = null;
                 Object.entries(data.stations).forEach(([code, series]) => {
                     const level = series.level[frame];
                     const discharge = series.discharge[frame];
                     readings.set(code, { water_level: level, discharge });
                     updateStationMarker(code, discharge);
-                    if (discharge != null) totalFlow += discharge;
+                    if (discharge != null) {
+                        totalFlow += discharge;
+                        if (!peakFlow || discharge > peakFlow.value) peakFlow = { code, value: discharge };
+                    }
                 });
+                // stat tiles follow the replay (restored by loadDashboard on finish)
+                $('total-flow').textContent = totalFlow.toLocaleString(undefined, { maximumFractionDigits: 1 });
+                $('peak-flow').textContent = peakFlow ? peakFlow.value.toFixed(1) : '—';
+                $('peak-station').textContent = peakFlow ? `${peakFlow.code} · m³/s · 2024 replay` : 'No discharge reported';
                 restyleRiver(readings);
                 const p1Level = data.stations['P.1'] ? data.stations['P.1'].level[frame] : null;
                 if (p1Level != null) state.p1Now = Number(p1Level);