fix: add per-test timeout to pytest.ini to prevent CI hangs

pytest.ini takes precedence over pyproject.toml [tool.pytest.ini_options]
so the timeout = 30 setting there was silently ignored. Add timeout = 30
and timeout_method = thread directly to pytest.ini so blocking tests are
killed after 30 s in CI.

pytest.ini

@@ -12,6 +12,11 @@ testpaths = tests
 # Async test support
 asyncio_mode = auto
 
+# Per-test timeout — prevents blocking I/O or infinite loops from hanging CI.
+# Tests that legitimately need longer can use @pytest.mark.timeout(N).
+timeout = 30
+timeout_method = thread
+
 # Coverage configuration (optional)
 # [tool:pytest]
 # addopts = --cov=modules --cov-report=html --cov-report=term-missing