feat(cfold): canonicalize custom test layout

tests/matrix-synapse/custom/test_health_check.py

@@ -0,0 +1,28 @@
+"""matrix-synapse — health-check parity port (Phase 2 P2).
+
+SOURCE: there is no `recipe-info/matrix-synapse/tests/health_check.py` in the recipe-maintainer
+corpus (the corpus's matrix-synapse tests are shell scripts targeting a persistent instance —
+see DECISIONS.md for the Q4 deeper-port deferral). This file is a Phase-2 health_check ALIGNED
+with the parity-port convention: HTTP 200 from the client API versions endpoint, which is the
+recipe's HEALTH_PATH and the canonical "is synapse up" signal.
+
+Runs in the custom tier against the shared post-install live deployment.
+"""
+
+from __future__ import annotations
+
+import os
+import sys
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "..", "runner"))
+from harness import http as harness_http  # noqa: E402
+
+
+def test_synapse_client_versions_returns_json(live_app):
+    """Verify /_matrix/client/versions returns 200 + a JSON document with a non-empty versions list."""
+    url = f"https://{live_app}/_matrix/client/versions"
+    status, body = harness_http.retry_http_get(url, expect_status=200, max_wait=60, interval=3)
+    assert status == 200, f"GET {url} HTTP {status} (expected 200)"
+    assert (
+        isinstance(body, dict) and isinstance(body.get("versions"), list) and body["versions"]
+    ), f"GET {url} did not return Matrix client-versions document: {body!r}"