feat(dashboard): add sensitive data toggle to flow chart

Add an eye toggle in the flow section header that masks sensitive node
labels (users, tokens, nodes, groups, channels) in the Sankey while keeping
model names visible. Masking only rewrites display text; nodes stay distinct
via their key so graph structure, links, and highlighting are unaffected.

web/default/src/features/dashboard/components/flow/flow-charts.tsx

@@ -94,6 +94,8 @@ import { FlowNodeFilterControl } from './flow-node-filter'
 
 interface FlowChartsProps {
   filters?: DashboardFilters
+  // When false, sensitive node labels are masked in the rendered Sankey.
+  sensitiveVisible?: boolean
 }
 
 const FLOW_METRIC_OPTIONS = [
@@ -340,6 +342,7 @@ export function FlowCharts(props: FlowChartsProps) {
     staleTime: 60_000,
   })
 
+  const maskSensitive = props.sensitiveVisible === false
   const flowData = useMemo(
     () =>
       buildDashboardFlowData(isLoading ? [] : (flowRows ?? []), metric, {
@@ -351,6 +354,7 @@ export function FlowCharts(props: FlowChartsProps) {
         visibleStages,
         topNodeLimit,
         overflowMode,
+        maskSensitive,
         deletedTokenLabel: (tokenId) => t('Deleted ({{id}})', { id: tokenId }),
         otherNodeLabel: (kind) => t(FLOW_OTHER_NODE_LABEL_KEYS[kind]),
       }),
@@ -366,6 +370,7 @@ export function FlowCharts(props: FlowChartsProps) {
       selectedUsers,
       topNodeLimit,
       visibleStages,
+      maskSensitive,
       t,
     ]
   )
@@ -468,6 +473,7 @@ export function FlowCharts(props: FlowChartsProps) {
     selectedNodes.map(flowNodeFilterKey).join(','),
     selectedUsers.join(','),
     visibleStages.join(','),
+    maskSensitive ? 'masked' : 'plain',
     flowRows?.length ?? 0,
     resolvedTheme,
   ].join('-')