Implement Phases 1-5: skeleton, OAuth, categories, video sync/feed, playback

- FastAPI + PostgreSQL + Alembic + React/Vite skeleton, Docker Compose, healthcheck
- Google OAuth (single allowed account), encrypted refresh token storage
- Subscriptions sync with pagination, uploads playlist batch fetch
- Categories CRUD, many-to-many channel assignment, category filtering
- Video sync (playlistItems + videos.list batching), cached feed with cursor
  pagination, background scheduler (APScheduler)
- Video detail page with YouTube embed player
- SPA fallback routing, optimistic UI updates, client-side query caching

40 backend tests covering OAuth allow-list, sync idempotency, cascade deletes,
cursor pagination, and category filtering.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/src/api/client.ts

@@ -0,0 +1,181 @@
+const AUTH_ERROR_MESSAGES: Record<string, string> = {
+  google_error: 'Google вернул ошибку авторизации',
+  invalid_state: 'Сессия авторизации устарела, попробуйте снова',
+  exchange_failed: 'Не удалось обменять код авторизации',
+  userinfo_failed: 'Не удалось получить данные аккаунта Google',
+  account_not_allowed: 'Этот Google-аккаунт не разрешён для входа',
+}
+
+export function authErrorMessage(code: string): string {
+  return AUTH_ERROR_MESSAGES[code] ?? 'Неизвестная ошибка авторизации'
+}
+
+async function request<T>(path: string, options: RequestInit = {}): Promise<T> {
+  const res = await fetch(path, {
+    credentials: 'include',
+    headers: { 'Content-Type': 'application/json', ...(options.headers ?? {}) },
+    ...options,
+  })
+  if (!res.ok) {
+    let detail = `${res.status}`
+    try {
+      const body = await res.json()
+      detail = body.detail ?? detail
+    } catch {
+      // ignore
+    }
+    throw new Error(detail)
+  }
+  return res.json()
+}
+
+export interface AuthStatus {
+  authenticated: boolean
+  connected: boolean
+  email: string | null
+}
+
+export function getAuthStatus() {
+  return request<AuthStatus>('/api/auth/status')
+}
+
+export function startGoogleAuth() {
+  window.location.href = '/api/auth/google/start'
+}
+
+export function logout() {
+  return request<{ ok: boolean }>('/api/auth/logout', { method: 'POST' })
+}
+
+export interface ChannelDto {
+  id: number
+  youtube_channel_id: string
+  title: string
+  description: string | null
+  thumbnail_url: string | null
+  uploads_playlist_id: string | null
+  subscribed: boolean
+  last_synced_at: string | null
+  category_ids: number[]
+}
+
+export function getChannel(channelId: number) {
+  return request<ChannelDto>(`/api/channels/${channelId}`)
+}
+
+export function listChannels(
+  params: { search?: string; categoryId?: number; uncategorized?: boolean } = {},
+) {
+  const qs = new URLSearchParams()
+  if (params.search) qs.set('search', params.search)
+  if (params.categoryId != null) qs.set('category_id', String(params.categoryId))
+  if (params.uncategorized) qs.set('uncategorized', 'true')
+  const suffix = qs.toString() ? `?${qs.toString()}` : ''
+  return request<ChannelDto[]>(`/api/channels${suffix}`)
+}
+
+export function setChannelCategories(channelId: number, categoryIds: number[]) {
+  return request<ChannelDto>(`/api/channels/${channelId}/categories`, {
+    method: 'PUT',
+    body: JSON.stringify({ category_ids: categoryIds }),
+  })
+}
+
+export interface CategoryDto {
+  id: number
+  name: string
+  slug: string
+  sort_order: number
+  channel_count: number
+}
+
+export function listCategories() {
+  return request<CategoryDto[]>('/api/categories')
+}
+
+export function createCategory(name: string) {
+  return request<CategoryDto>('/api/categories', {
+    method: 'POST',
+    body: JSON.stringify({ name }),
+  })
+}
+
+export function updateCategory(id: number, name: string) {
+  return request<CategoryDto>(`/api/categories/${id}`, {
+    method: 'PATCH',
+    body: JSON.stringify({ name }),
+  })
+}
+
+export function deleteCategory(id: number) {
+  return fetch(`/api/categories/${id}`, { method: 'DELETE', credentials: 'include' }).then((res) => {
+    if (!res.ok) throw new Error(`${res.status}`)
+  })
+}
+
+export function reorderCategories(categoryIds: number[]) {
+  return request<CategoryDto[]>('/api/categories/reorder', {
+    method: 'POST',
+    body: JSON.stringify({ category_ids: categoryIds }),
+  })
+}
+
+export interface SyncStatus {
+  status: string
+  started_at?: string
+  finished_at?: string | null
+  error?: string | null
+  running: boolean
+  [key: string]: unknown
+}
+
+export function getSyncStatus() {
+  return request<{ subscriptions: SyncStatus; videos: SyncStatus }>('/api/sync/status')
+}
+
+export function syncSubscriptions() {
+  return request<SyncStatus>('/api/sync/subscriptions', { method: 'POST' })
+}
+
+export function syncVideos() {
+  return request<SyncStatus>('/api/sync/videos', { method: 'POST' })
+}
+
+export interface FeedVideoDto {
+  youtube_video_id: string
+  title: string
+  description: string | null
+  channel: {
+    id: number
+    youtube_channel_id: string
+    title: string
+    thumbnail_url: string | null
+  }
+  thumbnail_url: string | null
+  published_at: string
+  duration_seconds: number | null
+  youtube_url: string
+  categories: { id: number; name: string }[]
+  local: {
+    available: boolean
+    status: string
+    progress_percent: number | null
+    media_url: string | null
+  }
+}
+
+export function getVideo(youtubeVideoId: string) {
+  return request<FeedVideoDto>(`/api/videos/${youtubeVideoId}`)
+}
+
+export function getFeed(
+  params: { categoryId?: number; uncategorized?: boolean; channelId?: number; cursor?: string } = {},
+) {
+  const qs = new URLSearchParams()
+  if (params.categoryId != null) qs.set('category_id', String(params.categoryId))
+  if (params.uncategorized) qs.set('uncategorized', 'true')
+  if (params.channelId != null) qs.set('channel_id', String(params.channelId))
+  if (params.cursor) qs.set('cursor', params.cursor)
+  const suffix = qs.toString() ? `?${qs.toString()}` : ''
+  return request<{ items: FeedVideoDto[]; next_cursor: string | null }>(`/api/feed${suffix}`)
+}