feat: M0 monorepo skeleton with services, clients, deploy and CI

- api/openapi.yaml: contract with /healthz, /readyz, /api/v1/server-info
- services/api (Go): api with oapi-codegen strict server, goose migrations,
  readiness checks for Postgres/Redis; storage-agent stub with internal token
- services/recommender (Python, uv): FastAPI health/readiness/internal status,
  `pipu-rec serve` and `pipu-rec analyze` entrypoints
- packages: generated api-client, core (server URL + server check),
  i18n (ru/en + dictionary check), design-tokens (CSS vars + TS from tokens.json)
- apps/web: Vite + React shell showing server status, language switch
- apps/mobile: Expo (SDK 53) Android app with server connect screen
- deploy: Dockerfiles, compose (prod + dev), nginx template, install/update scripts
- .gitea/workflows: ci.yml and tag-based release.yml (images, signed APK, release)
- scripts/version.mjs: version and Android versionCode from git tag
- tests/fixtures/music/generate.sh: synthetic test library via ffmpeg
- docs: versionCode formula, OpenAPI 3.0.3, dev instructions in README

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

packages/core/src/server.ts

@@ -0,0 +1,43 @@
+import type { ApiClient, ServerInfo } from '@pipu/api-client';
+
+/**
+ * Приводит введённый пользователем адрес сервера к виду `https://host[:port][/path]` без завершающего слеша.
+ * Без схемы подставляется https. Возвращает null, если адрес некорректен.
+ */
+export function normalizeServerUrl(input: string): string | null {
+  const raw = input.trim();
+  if (!raw) return null;
+  const withScheme = /^[a-z][a-z0-9+.-]*:\/\//i.test(raw) ? raw : `https://${raw}`;
+  let url: URL;
+  try {
+    url = new URL(withScheme);
+  } catch {
+    return null;
+  }
+  if (url.protocol !== 'https:' && url.protocol !== 'http:') return null;
+  if (!url.hostname) return null;
+  const path = url.pathname.replace(/\/+$/, '');
+  return `${url.protocol}//${url.host}${path}`;
+}
+
+export type ServerCheck =
+  | { status: 'ok'; info: ServerInfo }
+  | { status: 'unsupported_app'; info: ServerInfo }
+  | { status: 'offline'; error: string };
+
+/**
+ * Проверяет сервер через GET /api/v1/server-info.
+ * appVersionCode — versionCode Android-клиента; для веба не передаётся.
+ */
+export async function checkServer(client: ApiClient, appVersionCode?: number): Promise<ServerCheck> {
+  try {
+    const { data, error } = await client.GET('/api/v1/server-info');
+    if (!data) return { status: 'offline', error: error ? error.code : 'unknown' };
+    if (appVersionCode !== undefined && appVersionCode < data.min_android_version_code) {
+      return { status: 'unsupported_app', info: data };
+    }
+    return { status: 'ok', info: data };
+  } catch (e) {
+    return { status: 'offline', error: e instanceof Error ? e.message : String(e) };
+  }
+}