fix(kb-ui): SensitivityBadge tolerates an unset/unknown level

A kb.list row can arrive without a sensitivity (a claim/note, or older data);
SENSITIVITY[level] was then undefined and reading .tone crashed the whole
object list. Fall back to a neutral badge — never defaulting an unknown value
to "Open", which would misstate exposure. (Surfaced building the standalone
webapp against a real corpus.)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/_internal.tsx

@@ -117,7 +117,16 @@ const SENSITIVITY: Record<Sensitivity, { label: string; tone: string; icon: Reac
 };
 
 export const SensitivityBadge: FC<{ level: Sensitivity; className?: string }> = ({ level, className }) => {
-  const s = SENSITIVITY[level];
+  // A row can arrive without a sensitivity (e.g. a claim/note, or older data);
+  // fall back to a neutral badge rather than crash — and never default an
+  // unknown value to "Open", which would misstate its exposure.
+  const s =
+    SENSITIVITY[level] ?? {
+      label: level ?? "—",
+      tone: "bg-muted text-muted-foreground",
+      icon: null,
+      title: "Sensitivity not set.",
+    };
   return (
     <Badge tone={s.tone} icon={s.icon} className={className} title={s.title}>
       {s.label}