feat: taste onboarding for new listeners (M6)

- GET /onboarding offers the library's top artists (with album covers)
  and genres and says whether to show it (not done and < 10 plays);
  PUT /me/onboarding stores the choice or a skip (migration 00009).
- The recommender seeds the taste from it while the user has fewer than
  30 scored tracks: chosen artists' tracks +1, chosen genres +0.5.
- Web: onboarding replaces the wave on the home page until done or
  skipped; artist grid with covers, genre chips, at least 3 artists.
- e2e journey and the recommender DB test cover it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/pages/HomePage.tsx

@@ -1,5 +1,5 @@
 import { unwrap } from '@pipu/core';
-import { useQuery } from '@tanstack/react-query';
+import { useQuery, useQueryClient } from '@tanstack/react-query';
 import { useState } from 'react';
 import { useTranslation } from 'react-i18next';
 
@@ -24,6 +24,7 @@ import {
 import { cx, FormError, Icon } from '../shared/ui/ui';
 import { WaveButton } from '../widgets/wave/WaveButton';
 import s from './home.module.css';
+import { Onboarding } from './Onboarding';
 
 /** Иконки Material Symbols по именам из /wave/options. */
 const ICONS: Record<string, string> = {
@@ -44,8 +45,28 @@ const WAVE_COLORS: [string, string, string] = ['#2F80FF', '#7C5CFF', '#35D3FF'];
 
 type Tr = (key: string) => string;
 
-/** Главная (раскладка Center): кнопка «Моя волна» и под ней выбор занятия и настроения. */
+/** Главная: для нового пользователя без истории — сначала онбординг вкуса, затем волна. */
 export function HomePage() {
+  const session = useSession();
+  const queryClient = useQueryClient();
+  const onboarding = useQuery({
+    queryKey: ['onboarding'],
+    queryFn: async () => unwrap(await session.client.GET('/api/v1/onboarding')),
+    staleTime: Infinity,
+  });
+  if (onboarding.data?.required) {
+    return (
+      <Onboarding
+        options={onboarding.data}
+        onDone={() => queryClient.setQueryData(['onboarding'], { ...onboarding.data, required: false })}
+      />
+    );
+  }
+  return <WaveHome />;
+}
+
+/** Главная (раскладка Center): кнопка «Моя волна» и под ней выбор занятия и настроения. */
+function WaveHome() {
   const { t } = useTranslation();
   const tr = t as unknown as Tr;
   const session = useSession();