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/assets/dup-report.css

@@ -0,0 +1,50 @@
+/* The near-duplicate report, shared by KnowledgeView (notes/tasks) and
+   SnippetListView (snippets) so the two reports read as one feature. Load
+   with <style src="@/assets/dup-report.css" /> beside the view's scoped
+   block; the view keeps only its own extras (.dup-claimed, .dup-action).
+   Promoted from two identical scoped copies in #2903 (milestone 299). */
+.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;
+}