test(ci): scope pytest timeout to test bodies, not fixture setup

Why:
- Testcontainers' session-scoped container startup (~25s on a cold Docker
  cache) was charged against the global 10s pytest-timeout budget, causing
  every integration test to fail regardless of its own runtime.

Changes:
- Set timeout_func_only = true so the budget applies to the test function
  only, not fixture setup.

pyproject.toml

@@ -37,6 +37,11 @@ dev = [
 testpaths = ["tests"]
 asyncio_mode = "strict"
 timeout = 10
+# Bound the test function only, not fixture setup. Testcontainers' container
+# startup is charged to whichever test first pulls a session-scoped container
+# fixture; on a cold Docker cache that is ~25s and would trip the 10s budget
+# for every integration test, regardless of how fast the test itself is.
+timeout_func_only = true
 markers = [
     "unit: fast tests with no external services",
     "integration: tests against a real disposable service",