refactor(tradein/scraper-kit): yandex providers on shared _base.py (#2363)

F4c-yandex (epic #2277 Group F, parent #2352): migrate the SERP scraper's
BrowserFetcher construction onto build_browser_fetcher() from the Foundation
module (#2358, providers/_base.py) instead of local ad-hoc construction.

- yandex/serp.py::__aenter__ now calls build_browser_fetcher(config, source=,
  proxy_provider=, fetch_timeout_s=) instead of constructing BrowserFetcher(...)
  directly. Preserves the existing fetch_timeout_s=30 (see caveat below),
  endpoint/proxy_provider/use_pool resolution byte-for-byte. The retry/tarpit
  logic in fetch_around() (rotate_ip + sleep on status==0/JSON-error) is
  untouched, per the Foundation module's documented exclusion.

Left unchanged (deliberate, not an oversight):
- yandex/serp.py::_rotate_ip's curl_cffi AsyncSession(timeout=30) — this hits
  the mobile-proxy provider's own changeip API, not Yandex; it intentionally
  carries no impersonate/headers/proxy (same as the mirrored avito/serp.py
  rotate-ip session). Not listed among the _base.py docstring's documented
  extraction sites -- consistent exclusion, not a new one.
- yandex/detail.py -- no BrowserFetcher/curl_cffi construction exists in this
  file (uses BaseScraper's httpx-based _http_get). Nothing to migrate.
- yandex/newbuilding.py -- both BrowserFetcher(...) call sites take an
  OPTIONAL `config: ScraperConfig | None`, a genuinely different contract from
  build_browser_fetcher's mandatory `config`. Migrating would require making
  config mandatory (breaking admin.py:1511, yandex_newbuilding_sweep.py:353,
  and several tests that call without config -- out of scope for a call-site
  swap) and breaks test_scraper_kit_newbuilding_endpoint.py's "without config,
  endpoint=None" regression case (its SimpleNamespace mock lacks
  use_proxy_pool_browser, and the mock config path can never satisfy a
  mandatory-config helper). Left untouched; the class-bug #2322/#2330 this
  file already fixed (config now threaded, just not via the shared helper)
  remains fixed.

Also updates test_kit_serp_proxy_pool.py's 3 yandex-specific tests: they
monkeypatched the module-local `yandex_serp.BrowserFetcher` name, which the
migrated call path no longer references directly (it now goes through
scraper_kit.providers._base.build_browser_fetcher -> _base's own BrowserFetcher
import). Patch target moved to scraper_kit.providers._base.BrowserFetcher;
every assertion is unchanged -- this adapts the mock to the new (intentional)
call path, it does not weaken what the test verifies. Cian's tests in the same
file are untouched (cian/serp.py is not migrated yet, separate F4b issue).

tradein-mvp/backend/tests/test_kit_serp_proxy_pool.py

@@ -12,6 +12,16 @@ proxy_provider + use_pool=config.use_proxy_pool_browser в BrowserFetcher.
 
 BrowserFetcher монки-патчится на recording-заглушку в модуле каждого скрапера, так что
 реального HTTP к tradein-browser не происходит.
+
+Yandex (#2363, F4c миграция): `yandex/serp.py::__aenter__` больше не конструирует
+`BrowserFetcher(...)` напрямую — вызывает shared `build_browser_fetcher()` из
+`scraper_kit.providers._base`, который ВНУТРИ себя ссылается на СВОЙ собственный
+импорт `BrowserFetcher`. Патч локального имени `yandex_serp.BrowserFetcher` больше
+не перехватывает вызов (реальный `BrowserFetcher.__init__` конструировался бы, а
+`calls` оставался пуст) — патчим `scraper_kit.providers._base.BrowserFetcher`
+(реальную зависимость `build_browser_fetcher`), сохраняя все assertions как есть.
+Cian (`cian/serp.py`) пока НЕ мигрирован (F4b, отдельный issue) — там патч
+локального имени остаётся корректным.
 """
 
 from __future__ import annotations
@@ -84,7 +94,7 @@ def _config(*, use_pool: bool) -> types.SimpleNamespace:
 async def test_yandex_serp_wires_pool_when_flag_on(monkeypatch: pytest.MonkeyPatch) -> None:
     """proxy_provider + флаг on → BrowserFetcher получает провайдер + use_pool=True."""
     rec_fetcher, calls = _make_recorder()
-    monkeypatch.setattr(yandex_serp, "BrowserFetcher", rec_fetcher)
+    monkeypatch.setattr("scraper_kit.providers._base.BrowserFetcher", rec_fetcher)
     provider = _FakeProxyProvider()
 
     scraper = yandex_serp.YandexRealtyScraper(_config(use_pool=True), proxy_provider=provider)
@@ -101,7 +111,7 @@ async def test_yandex_serp_wires_pool_when_flag_on(monkeypatch: pytest.MonkeyPat
 async def test_yandex_serp_no_pool_by_default(monkeypatch: pytest.MonkeyPatch) -> None:
     """Без provider/флага → BrowserFetcher(proxy_provider=None, use_pool=False) — ship-dark."""
     rec_fetcher, calls = _make_recorder()
-    monkeypatch.setattr(yandex_serp, "BrowserFetcher", rec_fetcher)
+    monkeypatch.setattr("scraper_kit.providers._base.BrowserFetcher", rec_fetcher)
 
     scraper = yandex_serp.YandexRealtyScraper(_config(use_pool=False))
     async with scraper:
@@ -118,7 +128,7 @@ async def test_yandex_serp_provider_without_flag_stays_dark(
 ) -> None:
     """provider задан, но флаг off → use_pool=False (BrowserFetcher пул не трогает)."""
     rec_fetcher, calls = _make_recorder()
-    monkeypatch.setattr(yandex_serp, "BrowserFetcher", rec_fetcher)
+    monkeypatch.setattr("scraper_kit.providers._base.BrowserFetcher", rec_fetcher)
     provider = _FakeProxyProvider()
 
     scraper = yandex_serp.YandexRealtyScraper(_config(use_pool=False), proxy_provider=provider)

tradein-mvp/packages/scraper-kit/src/scraper_kit/providers/yandex/serp.py

@@ -51,6 +51,7 @@ from scraper_kit.browser_fetcher import BrowserFetcher
 from scraper_kit.house_type_normalizer import normalize_house_type
 from scraper_kit.price_brackets import get_price_seed_brackets
 from scraper_kit.pricing import BisectionConfig, ProbeFailPolicy, ProbeResult, walk_price_range
+from scraper_kit.providers._base import build_browser_fetcher
 
 if TYPE_CHECKING:
     from scraper_kit.contracts import ProxyProvider, ScraperConfig
@@ -506,13 +507,16 @@ class YandexRealtyScraper(BaseScraper):
 
         fetch_timeout_s=_YANDEX_BROWSER_FETCH_TIMEOUT_S (30s) ограничивает потери
         на один тайм-аутовый запрос: worst-case 30s×(1+retries)=90s на combo вместо 360s.
+
+        Собрано через shared `build_browser_fetcher()` (#2358 Foundation, #2363
+        миграция) — endpoint/use_pool берутся из `config` mandatory, footgun-класс
+        #2322/#2330 (пропущенный endpoint/use_pool) закрыт структурно.
         """
-        self._browser = BrowserFetcher(
+        self._browser = build_browser_fetcher(
+            self._config,
             source="yandex",
-            fetch_timeout_s=_YANDEX_BROWSER_FETCH_TIMEOUT_S,
-            endpoint=self._config.browser_http_endpoint,
             proxy_provider=self._proxy_provider,
-            use_pool=self._config.use_proxy_pool_browser,
+            fetch_timeout_s=_YANDEX_BROWSER_FETCH_TIMEOUT_S,
         )
         await self._browser.__aenter__()
         return self