feat(charts): hover dimming, end-of-line labels, and value-label toggle

- Hover: non-hovered lines fade to 15% opacity so active line pops out
- End labels: museum name rendered at the tip of each line (always visible,
  stays full-opacity even when dimmed) with 110px right-padding for space
- Labels toggle: button in chart controls shows/hides per-point value labels
- interaction mode set to nearest/no-intersect for responsive hover

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

src/components/Comparison.tsx

@@ -78,6 +78,7 @@ export default function PeriodSelectorDemo({ data, seasons, includeVAT, allowedM
   const [selMuseums,   setSelMuseums]   = useState<string[]>([]);
   const [metric,     setMetric]     = useState('revenue');
   const [gran,       setGran]       = useState('week');
+  const [showLabels, setShowLabels] = useState(false);
 
   const perm = useMemo(() => {
     if (!allowedMuseums || !allowedChannels) return [];
@@ -174,10 +175,12 @@ export default function PeriodSelectorDemo({ data, seasons, includeVAT, allowedM
         fill: false,
         pointRadius: gran==='week' ? 3 : 1,
         pointBackgroundColor: chartPalette[idx % chartPalette.length],
+        _isMuseumLine: true,
       };
     });
     return {
       tooltipLabels,
+      multiMuseum,
       data: {
         labels,
         datasets: [
@@ -204,13 +207,18 @@ export default function PeriodSelectorDemo({ data, seasons, includeVAT, allowedM
     };
   }, [data, prevData, currData, prevStart, prevEnd, currStart, currEnd, metric, getVal]);
 
-  const baseOpts = useMemo(() => createBaseOptions(false), []);
+  const baseOpts = useMemo(() => createBaseOptions(showLabels), [showLabels]);
   const { chartOpts } = useMemo(() => {
     const chartOpts: any = { ...baseOpts, plugins:{ ...baseOpts.plugins, legend:{ position:'top', align:'end', labels:{ boxWidth:12, padding:12 } } } };
     return { chartOpts };
   }, [baseOpts]);
   const trendOpts: any = useMemo(() => ({
     ...chartOpts,
+    interaction: { mode: 'nearest', intersect: false },
+    layout: {
+      ...chartOpts.layout,
+      padding: { ...(chartOpts.layout?.padding ?? {}), right: trendResult.multiMuseum ? 110 : 5 },
+    },
     plugins: {
       ...chartOpts.plugins,
       tooltip: {
@@ -220,7 +228,7 @@ export default function PeriodSelectorDemo({ data, seasons, includeVAT, allowedM
         }
       }
     }
-  }), [chartOpts, trendResult.tooltipLabels]);
+  }), [chartOpts, trendResult.tooltipLabels, trendResult.multiMuseum]);
 
   const metricOpts = [
     { value:'revenue', label:L.revenue }, { value:'visitors', label:L.visitors },
@@ -320,6 +328,8 @@ export default function PeriodSelectorDemo({ data, seasons, includeVAT, allowedM
               {metricOpts.map(o => <button key={o.value} type="button" aria-pressed={metric===o.value} className={`alt-ctrl${metric===o.value?' alt-ctrl-on':''}`} onClick={() => setMetric(o.value)}>{o.label}</button>)}
               <div className="alt-ctrl-sep" />
               {granOpts.map(o => <button key={o.value} type="button" aria-pressed={gran===o.value} className={`alt-ctrl${gran===o.value?' alt-ctrl-on':''}`} onClick={() => setGran(o.value)}>{o.label}</button>)}
+              <div className="alt-ctrl-sep" />
+              <button type="button" aria-pressed={showLabels} className={`alt-ctrl${showLabels?' alt-ctrl-on':''}`} onClick={() => setShowLabels(v => !v)}>{'Labels'}</button>
             </div>
           </div>
           <div className="alt-chart-wrap"><Line data={trendData} options={trendOpts} /></div>

src/components/Dashboard.tsx

@@ -37,6 +37,7 @@ export default function DashboardDemo({ data, seasons: _seasons, includeVAT, set
   const [selMuseums,   setSelMuseums]   = useState<string[]>([]);
   const [metric,     setMetric]     = useState('revenue');
   const [gran,       setGran]       = useState('week');
+  const [showLabels, setShowLabels] = useState(false);
   const [museumChartType,   setMuseumChartType]   = useState<'bar'|'pie'>('bar');
   const [channelChartType,  setChannelChartType]  = useState<'bar'|'pie'>('pie');
   const [districtChartType, setDistrictChartType] = useState<'bar'|'pie'>('pie');
@@ -135,10 +136,12 @@ export default function DashboardDemo({ data, seasons: _seasons, includeVAT, set
         fill: false,
         pointRadius: gran==='week' ? 3 : 1,
         pointBackgroundColor: chartPalette[idx % chartPalette.length],
+        _isMuseumLine: true,
       };
     });
     return {
       tooltipLabels,
+      multiMuseum,
       data: {
         labels,
         datasets: [
@@ -201,7 +204,7 @@ export default function DashboardDemo({ data, seasons: _seasons, includeVAT, set
   const currCapture  = currPilgrims ? currM.visitors/currPilgrims*100 : null;
   const prevCapture  = prevPilgrims ? prevM.visitors/prevPilgrims*100 : null;
 
-  const baseOpts  = useMemo(() => createBaseOptions(false), []);
+  const baseOpts  = useMemo(() => createBaseOptions(showLabels), [showLabels]);
   const { chartOpts, barHorizOpts, barNoLegend } = useMemo(() => {
     const chartOpts: any = { ...baseOpts, plugins:{ ...baseOpts.plugins, legend:{ position:'top', align:'end', labels:{ boxWidth:10, padding:10, font:{ size:11 } } } } };
     const barHorizOpts: any = { ...chartOpts, indexAxis:'y', plugins:{ ...chartOpts.plugins, legend:{ display:false } } };
@@ -210,6 +213,11 @@ export default function DashboardDemo({ data, seasons: _seasons, includeVAT, set
   }, [baseOpts]);
   const trendOpts: any = useMemo(() => ({
     ...chartOpts,
+    interaction: { mode: 'nearest', intersect: false },
+    layout: {
+      ...chartOpts.layout,
+      padding: { ...(chartOpts.layout?.padding ?? {}), right: trendResult.multiMuseum ? 110 : 5 },
+    },
     plugins: {
       ...chartOpts.plugins,
       tooltip: {
@@ -219,7 +227,7 @@ export default function DashboardDemo({ data, seasons: _seasons, includeVAT, set
         }
       }
     }
-  }), [chartOpts, trendResult.tooltipLabels]);
+  }), [chartOpts, trendResult.tooltipLabels, trendResult.multiMuseum]);
 
   const pieOptions: any = useMemo(() => ({
     responsive: true, maintainAspectRatio: false,
@@ -297,6 +305,8 @@ export default function DashboardDemo({ data, seasons: _seasons, includeVAT, set
               {metricOpts.map(o => <button key={o.value} type="button" aria-pressed={metric===o.value} className={`alt-ctrl${metric===o.value?' alt-ctrl-on':''}`} onClick={() => setMetric(o.value)}>{o.label}</button>)}
               <div className="alt-ctrl-sep" />
               {granOpts.map(o => <button key={o.value} type="button" aria-pressed={gran===o.value} className={`alt-ctrl${gran===o.value?' alt-ctrl-on':''}`} onClick={() => setGran(o.value)}>{o.label}</button>)}
+              <div className="alt-ctrl-sep" />
+              <button type="button" aria-pressed={showLabels} className={`alt-ctrl${showLabels?' alt-ctrl-on':''}`} onClick={() => setShowLabels(v => !v)}>{'Labels'}</button>
             </div>
           </div>
           <div className="alt-chart-wrap alt-chart-wrap--tall"><Line data={trendData} options={trendOpts} /></div>

src/config/chartConfig.ts

@@ -134,6 +134,49 @@ export const createBaseOptions = (showDataLabels: boolean): any => {
   };
 };
 
+// Hover-dim + end-of-line name labels for multi-museum trend charts.
+// Only activates for charts that have datasets marked with _isMuseumLine.
+const trendLinePlugin = {
+  id: 'trendLineOverlay',
+  beforeDatasetDraw(chart: any, args: any) {
+    if (!chart.data.datasets.some((ds: any) => ds._isMuseumLine)) return;
+    const active = chart.getActiveElements();
+    if (active.length === 0) return;
+    if (active[0].datasetIndex !== args.index) {
+      chart.ctx.save();
+      chart.ctx.globalAlpha = 0.15;
+    }
+  },
+  afterDatasetDraw(chart: any, args: any) {
+    if (!chart.data.datasets.some((ds: any) => ds._isMuseumLine)) return;
+    const ds = chart.data.datasets[args.index] as any;
+    const active = chart.getActiveElements();
+    const isDimmed = active.length > 0 && active[0].datasetIndex !== args.index;
+    if (isDimmed) chart.ctx.restore();
+    if (!ds._isMuseumLine) return;
+    const meta = chart.getDatasetMeta(args.index);
+    if (meta.hidden) return;
+    const vals = ds.data as number[];
+    let lastIdx = vals.length - 1;
+    while (lastIdx > 0 && !vals[lastIdx]) lastIdx--;
+    if (!vals[lastIdx]) return;
+    const pt = meta.data[lastIdx] as any;
+    if (!pt) return;
+    const name: string = ds.label;
+    const label = name.length > 22 ? name.slice(0, 20) + '…' : name;
+    const ctx = chart.ctx;
+    ctx.save();
+    ctx.font = '600 9px system-ui,-apple-system,sans-serif';
+    ctx.fillStyle = ds.borderColor;
+    ctx.textAlign = 'left';
+    ctx.textBaseline = 'middle';
+    ctx.fillText(label, pt.x + 6, pt.y);
+    ctx.restore();
+  }
+};
+
+ChartJS.register(trendLinePlugin);
+
 export const lineDatasetDefaults = {
   borderWidth: 2,
   tension: 0.4,