feat(dashboard): add traffic flow sankey chart (#5465)

* feat(dashboard): add traffic flow sankey chart

Add dashboard flow APIs and a Sankey-based flow view with user, optional API key, model, and channel layers.\n\nReuse the dashboard VChart palette, add precise link/node tooltips and interactions, and cover filtering, layer ordering, color stability, and error states with tests.

* feat: build flow chart from quota data

---------

Co-authored-by: CaIon <i@caion.me>

web/default/src/components/multi-select.tsx

@@ -66,6 +66,11 @@ interface MultiSelectProps {
    * Hidden values remain searchable/removable from the dropdown.
    */
   maxVisibleChips?: number
+  /**
+   * Replaces individual chips with a compact summary while preserving the
+   * normal dropdown/search behaviour.
+   */
+  renderSelectedSummary?: (values: string[]) => React.ReactNode
   /**
    * When true, clicking a chip's label copies its value to the clipboard
    * instead of being inert. The remove (×) button keeps its own behaviour.
@@ -258,6 +263,14 @@ export function MultiSelect(props: MultiSelectProps) {
       >
         <ComboboxValue>
           {(values: string[]) => {
+            if (props.renderSelectedSummary) {
+              return (
+                <span className='bg-muted text-muted-foreground flex h-[calc(--spacing(5.25))] w-fit items-center justify-center rounded-sm px-1.5 font-mono text-xs font-medium whitespace-nowrap'>
+                  {props.renderSelectedSummary(values)}
+                </span>
+              )
+            }
+
             const shouldLimit =
               typeof props.maxVisibleChips === 'number' && !expanded
             const visibleValues = shouldLimit
@@ -327,7 +340,11 @@ export function MultiSelect(props: MultiSelectProps) {
         </ComboboxValue>
         <ComboboxChipsInput
           id={props.id}
-          placeholder={props.selected.length === 0 ? placeholder : undefined}
+          placeholder={
+            props.selected.length === 0 && !props.renderSelectedSummary
+              ? placeholder
+              : undefined
+          }
           onKeyDown={handleKeyDown}
           aria-label={placeholder}
         />