feat(stats): add v1 immersion stats dashboard (#19)

stats/src/components/vocabulary/pos-helpers.tsx

@@ -0,0 +1,38 @@
+import type { VocabularyEntry } from '../../types/stats';
+
+const POS_COLORS: Record<string, string> = {
+  noun: 'bg-ctp-blue/15 text-ctp-blue',
+  verb: 'bg-ctp-green/15 text-ctp-green',
+  adjective: 'bg-ctp-mauve/15 text-ctp-mauve',
+  adverb: 'bg-ctp-peach/15 text-ctp-peach',
+  particle: 'bg-ctp-overlay0/15 text-ctp-overlay0',
+  auxiliary_verb: 'bg-ctp-overlay0/15 text-ctp-overlay0',
+  conjunction: 'bg-ctp-overlay0/15 text-ctp-overlay0',
+  prenominal: 'bg-ctp-yellow/15 text-ctp-yellow',
+  suffix: 'bg-ctp-flamingo/15 text-ctp-flamingo',
+  prefix: 'bg-ctp-flamingo/15 text-ctp-flamingo',
+  interjection: 'bg-ctp-rosewater/15 text-ctp-rosewater',
+};
+
+const DEFAULT_POS_COLOR = 'bg-ctp-surface1 text-ctp-subtext0';
+
+export function posColor(pos: string): string {
+  return POS_COLORS[pos] ?? DEFAULT_POS_COLOR;
+}
+
+export function PosBadge({ pos }: { pos: string }) {
+  return (
+    <span className={`rounded-full px-2 py-0.5 text-[11px] font-medium ${posColor(pos)}`}>
+      {pos.replace(/_/g, ' ')}
+    </span>
+  );
+}
+
+const PARTICLE_POS = new Set(['particle', 'auxiliary_verb', 'conjunction']);
+
+export function isFilterable(entry: VocabularyEntry): boolean {
+  if (PARTICLE_POS.has(entry.partOfSpeech ?? '')) return true;
+  if (entry.headword.length === 1 && /[\u3040-\u309F\u30A0-\u30FF]/.test(entry.headword))
+    return true;
+  return false;
+}