ci: block new async blocking calls

tests/fixtures/architecture/async-blocking-baseline.json

@@ -0,0 +1,3 @@
+{
+  "app/agent/middleware/activity_log.py:ActivityLogMiddleware._append_activity:os.open": 1
+}

tests/test_async_blocking_gate.py

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+"""async 阻塞调用 ratchet 与 debug 模式测试。"""
+
+import asyncio
+
+import pytest
+
+from scripts.architecture.async_blocking import compare_async_blocking
+
+
+def test_async_blocking_ratchet_allows_removal_and_rejects_growth() -> None:
+    """存量减少合法，新增或增加直接阻塞调用必须失败。"""
+    baseline = {
+        "app/api/a.py:stream:Path.read_text": 2,
+        "app/agent/a.py:run:time.sleep": 1,
+    }
+    reduced = {"app/api/a.py:stream:Path.read_text": 1}
+    increased = {
+        "app/api/a.py:stream:Path.read_text": 3,
+        "app/application/a.py:load:requests.get": 1,
+    }
+
+    assert compare_async_blocking(baseline, reduced) == []
+    problems = compare_async_blocking(baseline, increased)
+    assert any("增长" in problem for problem in problems)
+    assert any("新增" in problem for problem in problems)
+
+
+@pytest.mark.asyncio
+async def test_asyncio_debug_is_enabled_for_async_tests() -> None:
+    """专项异步测试必须启用慢 callback 和阻塞诊断所需的 debug 模式。"""
+    assert asyncio.get_running_loop().get_debug() is True