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>

apps/web/src/App.tsx

@@ -0,0 +1,57 @@
+import { createApiClient, type ApiClient } from '@pipu/api-client';
+import { checkServer } from '@pipu/core';
+import { SUPPORTED_LOCALES } from '@pipu/i18n';
+import { useQuery } from '@tanstack/react-query';
+import { useTranslation } from 'react-i18next';
+
+const defaultClient = createApiClient();
+
+export function App({ client = defaultClient }: { client?: ApiClient }) {
+  const { t, i18n } = useTranslation();
+  const server = useQuery({ queryKey: ['server-info'], queryFn: () => checkServer(client) });
+
+  return (
+    <div className="shell">
+      <header className="top">
+        <div className="logo">
+          <span className="logo-dot" aria-hidden />
+          {t('app.name')}
+        </div>
+        <div className="langs" role="group" aria-label={t('language.label')}>
+          {SUPPORTED_LOCALES.map((l) => (
+            <button
+              key={l}
+              type="button"
+              aria-pressed={i18n.language === l}
+              onClick={() => {
+                void i18n.changeLanguage(l);
+                document.documentElement.lang = l;
+              }}
+            >
+              {l.toUpperCase()}
+            </button>
+          ))}
+        </div>
+      </header>
+      <main className="main">
+        <section className="card">
+          <h1>{t('app.name')}</h1>
+          <p className="muted">{t('app.tagline')}</p>
+          {server.data?.status === 'ok' ? (
+            <div className="status" data-state="ok" role="status">
+              {t('server.online', { version: server.data.info.version })}
+            </div>
+          ) : server.data ? (
+            <div className="status" data-state="error" role="status">
+              {t('server.offline')}
+            </div>
+          ) : (
+            <div className="status" data-state="pending" role="status">
+              {t('server.checking')}
+            </div>
+          )}
+        </section>
+      </main>
+    </div>
+  );
+}