test: skip network/live crawl by default; fix settings e2e key

- pytest_collection_modifyitems: skip @pytest.mark.network unless PROXYPOOL_RUN_NETWORK_TESTS=1
- Document opt-in in tests/README.md
- e2e: replace removed crawl_timeout with validation_timeout

Made-with: Cursor

tests/conftest.py

@@ -11,6 +11,26 @@ if sys.platform == "win32":
     asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
 
 import pytest
+
+
+def _network_tests_enabled() -> bool:
+    v = os.environ.get("PROXYPOOL_RUN_NETWORK_TESTS", "").strip().lower()
+    return v in ("1", "true", "yes", "on")
+
+
+def pytest_collection_modifyitems(config, items) -> None:
+    """默认跳过 @pytest.mark.network，避免全量 pytest 触发真实爬取卡住数十分种。"""
+    if _network_tests_enabled():
+        return
+    skip = pytest.mark.skip(
+        reason=(
+            "外网/真实爬取用例默认跳过。需要验收时设置环境变量 "
+            "PROXYPOOL_RUN_NETWORK_TESTS=1 后再运行对应文件或 -m network。"
+        )
+    )
+    for item in items:
+        if "network" in item.keywords:
+            item.add_marker(skip)
 import pytest_asyncio
 from typing import AsyncGenerator
 from httpx import AsyncClient, ASGITransport