refactor(frontend): the near-duplicate report rules shared via dup-report.css — KnowledgeView and SnippetListView carried identical scoped copies (#2903, milestone 299 step 5, part 2)

KnowledgeView's own comment asked for this promotion once a second view grew the
panel. The sheet carries .dup-panel / .dup-empty,.dup-head / .dup-group /
.dup-members / .dup-member(+:hover) / .dup-score; each view keeps only its
extras (.dup-claimed, .dup-action).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/views/KnowledgeView.vue

@@ -574,6 +574,7 @@ onUnmounted(() => {
   </div>
 </template>
 
+<style src="@/assets/dup-report.css" />
 <style scoped>
 /* ── Root layout ─────────────────────────────────────────── */
 .knowledge-root {
@@ -1042,56 +1043,6 @@ onUnmounted(() => {
 }
 
 
-/* ── Near-duplicate report ──────────────────────────────────────────────────
-   Mirrors SnippetListView's panel so the two reports read as one feature.
-   Scoped styles can't be shared across SFCs; if a third view ever grows this
-   panel, promote the family to components.css and record it (#2464's rule:
-   two-or-more is when a recipe earns the shared sheet). */
-.dup-panel {
-  margin-bottom: 1.25rem;
-  padding: 0.85rem 1rem;
-  border: 1px solid var(--fs-border-color);
-  border-radius: 8px;
-  background: var(--fs-surface-hover);
-}
-.dup-empty,
-.dup-head {
-  margin: 0 0 0.5rem;
-  font-size: 0.85rem;
-  color: var(--fs-text-tertiary);
-}
-.dup-empty { margin-bottom: 0; }
-.dup-group {
-  display: flex;
-  align-items: center;
-  gap: 0.75rem;
-  flex-wrap: wrap;
-  padding: 0.5rem 0;
-  border-top: 1px solid var(--fs-border-color);
-}
-.dup-members {
-  display: flex;
-  gap: 0.4rem;
-  flex-wrap: wrap;
-  flex: 1 1 20rem;
-  min-width: 0;
-}
-.dup-member {
-  font-size: 0.8rem;
-  padding: 0.1rem 0.45rem;
-  border-radius: 4px;
-  background: color-mix(in srgb, var(--fs-text-tertiary) 12%, transparent);
-  color: var(--fs-text-primary);
-  text-decoration: none;
-  overflow-wrap: anywhere;
-}
-.dup-member:hover { background: var(--fs-surface-hover); }
-.dup-score {
-  font-size: 0.75rem;
-  color: var(--fs-text-tertiary);
-  font-variant-numeric: tabular-nums;
-  white-space: nowrap;
-}
 /* A set someone already ruled on — quiet, not celebratory: it means "skip". */
 .dup-claimed {
   font-size: 0.72rem;