feat(web): заготовка веб-клиента на Vite + React 19 + TypeScript strict

- стек по §5.2: React 19, React Router, TanStack Query, Zustand, Tailwind CSS 4,
  i18next (ru/en), Vitest + Testing Library
- дизайн-токены §3 docs/client-web.md (тёмная тема по умолчанию, светлая, accent)
- типизированный API-клиент §8.1: единый формат ошибок, ApiError с кодом
- App: экран состояния фундамента с readz/meta, локализация ошибок по code
- тесты: клиент API, форматирование, рендер App (успех/ошибка кода/сеть)
- eslint + prettier + tsc strict; initial JS 97.6 KB gzip

web/src/api/client.ts

@@ -0,0 +1,107 @@
+export interface ApiErrorBody {
+  error: {
+    code: string;
+    message: string;
+    details?: Record<string, unknown>;
+  };
+}
+
+export class ApiError extends Error {
+  readonly code: string;
+  readonly status: number;
+  readonly details?: Record<string, unknown>;
+
+  constructor(status: number, code: string, message: string, details?: Record<string, unknown>) {
+    super(message);
+    this.name = 'ApiError';
+    this.status = status;
+    this.code = code;
+    if (details !== undefined) {
+      this.details = details;
+    }
+  }
+}
+
+const API_PREFIX = '/api/v1';
+
+export function isApiErrorPayload(value: unknown): value is ApiErrorBody['error'] {
+  if (typeof value !== 'object' || value === null) {
+    return false;
+  }
+  const candidate = value as { code?: unknown; message?: unknown };
+  return typeof candidate.code === 'string' && typeof candidate.message === 'string';
+}
+
+export function apiErrorCode(error: unknown): string | null {
+  if (error === null || typeof error !== 'object') {
+    return null;
+  }
+  const payload = (error as { apiError?: unknown }).apiError;
+  return isApiErrorPayload(payload) ? payload.code : null;
+}
+
+export interface RequestOptions {
+  method?: 'GET' | 'POST' | 'PATCH' | 'PUT' | 'DELETE';
+  body?: unknown;
+  signal?: AbortSignal;
+  headers?: Record<string, string>;
+}
+
+export function parsePayload(text: string, contentType: string | null): unknown {
+  if (text.length === 0) {
+    return null;
+  }
+  if (contentType !== null && !contentType.includes('application/json')) {
+    return null;
+  }
+  try {
+    return JSON.parse(text) as unknown;
+  } catch {
+    return null;
+  }
+}
+
+export async function request<T>(path: string, options: RequestOptions = {}): Promise<T> {
+  const init: RequestInit = {
+    method: options.method ?? 'GET',
+    credentials: 'same-origin',
+    headers: {
+      Accept: 'application/json',
+      ...(options.body === undefined ? {} : { 'Content-Type': 'application/json' }),
+      ...options.headers,
+    },
+  };
+  if (options.body !== undefined) {
+    init.body = JSON.stringify(options.body);
+  }
+  if (options.signal !== undefined) {
+    init.signal = options.signal;
+  }
+
+  const response = await fetch(`${API_PREFIX}${path}`, init);
+  const text = await response.text();
+  const payload = parsePayload(text, response.headers.get('Content-Type'));
+
+  if (!response.ok) {
+    const envelope =
+      typeof payload === 'object' && payload !== null
+        ? (payload as { error?: unknown }).error
+        : undefined;
+    if (isApiErrorPayload(envelope)) {
+      const error = new ApiError(
+        response.status,
+        envelope.code,
+        envelope.message,
+        envelope.details,
+      );
+      Object.defineProperty(error, 'apiError', {
+        value: envelope,
+        enumerable: false,
+        writable: false,
+      });
+      throw error;
+    }
+    throw new ApiError(response.status, 'internal.error', 'unexpected response');
+  }
+  return payload as T;
+}

web/src/api/health.ts

@@ -0,0 +1,13 @@
+import { request } from './client';
+
+export interface ReadinessResponse {
+  status: 'ready' | 'unavailable';
+  version: string;
+  checks: Record<string, string>;
+}
+
+export const readyQueryKey = ['readyz'] as const;
+
+export function fetchReadiness(signal?: AbortSignal): Promise<ReadinessResponse> {
+  return request<ReadinessResponse>('/readyz', signal === undefined ? {} : { signal });
+}

web/src/api/meta.ts

@@ -0,0 +1,30 @@
+import { request } from './client';
+
+export interface InstanceFeatures {
+  registration_enabled: boolean;
+  anti_bot_enabled: boolean;
+  voice_enabled: boolean;
+  web_push_enabled: boolean;
+  oauth_enabled: boolean;
+  passkeys_enabled: boolean;
+}
+
+export interface InstanceMeta {
+  name: string;
+  version: string;
+  commit: string;
+  build_date: string;
+  api_version: string;
+  base_url: string;
+  files_url: string;
+  gateway_url: string;
+  rtc_path: string;
+  max_upload_size: number;
+  features: InstanceFeatures;
+}
+
+export const metaQueryKey = ['meta'] as const;
+
+export function fetchMeta(signal?: AbortSignal): Promise<InstanceMeta> {
+  return request<InstanceMeta>('/meta', signal === undefined ? {} : { signal });
+}