Wire donut selection feedback + unexport FeedbackBucketKey

Two more bugbot findings on the Usage strip.

- Donuts now render selected slices with a darker stroke (3px vs 2px) and
  unselected slices at 50% opacity when any slice is selected — matching
  the bar/stacked cards' "dim only when something is active" pattern.
  `UsageInsightsStrip` maps `deviceKind` and `language` chips onto the
  donut data via the existing `isDimSelected` helper.
- `FeedbackBucketKey` is only used inside `UsageStackedBarCard.tsx` (via the
  `onSegmentClick` prop signature); drop the export and make it local.

https://claude.ai/code/session_01LEZrzpRouYiybD1thXkGh5

Author: claude

mcpjam-inspector/client/src/components/shared/usage-insights/UsageDonutPairCard.tsx

@@ -44,6 +44,10 @@ function Donut({
   onClick?: (datum: BarDatum) => void;
 }) {
   const hasData = data.length > 0 && data.some((d) => d.count > 0);
+  // Same "only dim when something is selected" semantics as UsageBarCard so
+  // donuts stay at full opacity with nothing active and visually highlight
+  // the selected slice(s) otherwise.
+  const hasSelection = data.some((d) => d.isSelected);
 
   if (!hasData) {
     return (
@@ -76,7 +80,11 @@ function Donut({
             <Cell
               key={entry.key}
               fill={PALETTE[index % PALETTE.length]}
-              stroke="var(--background)"
+              stroke={
+                entry.isSelected ? "var(--foreground)" : "var(--background)"
+              }
+              strokeWidth={entry.isSelected ? 3 : 2}
+              opacity={!hasSelection || entry.isSelected ? 1 : 0.5}
             />
           ))}
         </Pie>

mcpjam-inspector/client/src/components/shared/usage-insights/UsageInsightsStrip.tsx

@@ -253,9 +253,15 @@ export function UsageInsightsStrip({
           <UsageDonutPairCard
             title="Device & language"
             leftLabel="Device"
-            leftData={devices}
+            leftData={devices.map((d) => ({
+              ...d,
+              isSelected: isDimSelected("deviceKind", d.key),
+            }))}
             rightLabel="Language"
-            rightData={languages}
+            rightData={languages.map((l) => ({
+              ...l,
+              isSelected: isDimSelected("language", l.key),
+            }))}
             onLeftSliceClick={(datum) =>
               onToggleChip({
                 kind: "dimension",

mcpjam-inspector/client/src/components/shared/usage-insights/UsageStackedBarCard.tsx

@@ -12,7 +12,9 @@ import {
   type ChartConfig,
 } from "@/components/ui/chart";
 
-export type FeedbackBucketKey = "positive" | "neutral" | "negative" | "none";
+// Local helper — every consumer goes through the `onSegmentClick` prop
+// signature, so nothing outside this file imports the union directly.
+type FeedbackBucketKey = "positive" | "neutral" | "negative" | "none";
 
 export type StackedDatum = {
   key: string;