fix: unify activity labels and Russian plurals

apps/web/src/lib/api.ts

@@ -12,6 +12,8 @@ export type DictionaryItem = { id: string; slug: string; name_ru: string };
 export type OfficialRecord = { id: string; fish: string; weight_g: number; waterbody: string; bait: string | null; player_name: string | null; record_date: string | null; category: string | null; region: string | null; source_url: string | null };
 export type ImportRun = { id: string; started_at: string; finished_at: string | null; status: string; source_url: string; rows_seen: number; rows_created: number; rows_updated: number; error_summary: string | null };
 
+export { activityLevel, ago, kg, plural } from "./presentation";
+
 const base = process.env.API_INTERNAL_URL || import.meta.env.API_INTERNAL_URL || "http://localhost:8000";
 
 export async function api<T>(path: string): Promise<T> {
@@ -19,9 +21,3 @@ export async function api<T>(path: string): Promise<T> {
   if (!response.ok) throw new Error(`API ${response.status}`);
   return response.json() as Promise<T>;
 }
-
-export function kg(grams: number) { return `${(grams / 1000).toFixed(2)} кг`; }
-export function ago(value: string) {
-  const minutes = Math.max(0, Math.round((Date.now() - new Date(value).getTime()) / 60000));
-  return minutes < 60 ? `${minutes} мин назад` : `${Math.floor(minutes / 60)} ч назад`;
-}

apps/web/src/lib/presentation.ts

@@ -0,0 +1,22 @@
+export function kg(grams: number) { return `${(grams / 1000).toFixed(2)} кг`; }
+
+export function plural(number: number, forms: readonly [string, string, string]) {
+  const absolute = Math.abs(number) % 100;
+  const last = absolute % 10;
+  if (absolute > 10 && absolute < 20) return forms[2];
+  if (last === 1) return forms[0];
+  if (last >= 2 && last <= 4) return forms[1];
+  return forms[2];
+}
+
+export function activityLevel(score: number) {
+  if (score >= 80) return { short: "Очень высокий", description: "Очень высокая активность" };
+  if (score >= 60) return { short: "Высокий", description: "Высокая активность" };
+  if (score >= 40) return { short: "Средний", description: "Средняя активность" };
+  return { short: "Низкий", description: "Низкая активность" };
+}
+
+export function ago(value: string) {
+  const minutes = Math.max(0, Math.round((Date.now() - new Date(value).getTime()) / 60000));
+  return minutes < 60 ? `${minutes} мин назад` : `${Math.floor(minutes / 60)} ч назад`;
+}