feat(indexnow): add IndexNow key file and trigger script

- public/15455d9f2c7b473bb04336055b792ec9.txt — ownership-ключ для Yandex/Bing
- scripts/indexnow.js — собирает URL из dist/sitemap-*.xml (fallback: remote sitemap-index), шлёт на yandex.com/indexnow и api.indexnow.org/indexnow
- package.json: npm run indexnow
- .gitea/workflows/deploy.yml: после успешного deploy чекаут + node + npm run indexnow (не блокирует пайплайн через || true)

.gitea/workflows/deploy.yml

@@ -48,3 +48,14 @@ jobs:
           curl -fsS -o /dev/null -w "HEALTH HTTP %{http_code}\n" "$HEALTH_URL"
           docker image prune -af --filter "until=168h" >/dev/null 2>&1 || true
           REMOTE
+
+      - name: Checkout repo for IndexNow
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+
+      - name: Notify IndexNow (Yandex/Bing)
+        run: npm run indexnow || true