lint: ruff format + one auto-fix so the push self-test is green again

`scripts/lint.sh --fix` from the pinned lint devshell: 90 Python files
reformatted (ruff format, mechanical) and one C420 (dict comprehension →
dict.fromkeys) in tests/unit/test_f211_sso_skip.py. The push self-test had
been failing at the lint stage since build 1313 (2026-08-31) on exactly
these files; nothing else changed.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FqkQq3CDmFWcQ7u1LzoyRz

tests/matrix-synapse/custom/test_federation_version.py

@@ -34,12 +34,12 @@ def test_federation_version_endpoint(live_app):
     assert status == 200, f"GET {url} HTTP {status} (expected 200)"
     assert isinstance(body, dict), f"federation version returned non-dict: {type(body).__name__}"
     server = body.get("server")
-    assert isinstance(
-        server, dict
-    ), f"federation version response missing 'server' envelope: {body!r}"
+    assert isinstance(server, dict), (
+        f"federation version response missing 'server' envelope: {body!r}"
+    )
     name = server.get("name")
     assert name == "Synapse", f"server.name={name!r}, expected 'Synapse'"
     version = server.get("version")
-    assert (
-        isinstance(version, str) and len(version) > 0
-    ), f"server.version is not a non-empty string: {version!r}"
+    assert isinstance(version, str) and len(version) > 0, (
+        f"server.version is not a non-empty string: {version!r}"
+    )

tests/matrix-synapse/custom/test_health_check.py

@@ -23,6 +23,6 @@ def test_synapse_client_versions_returns_json(live_app):
     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}"
+    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}"
+    )

tests/matrix-synapse/custom/test_register_and_message.py

@@ -127,8 +127,7 @@ def _admin_register(domain: str, secret: str, username: str, password: str, admi
         if r["status"] == 200:
             if attempt > 1:
                 print(
-                    f"  [register] {username}: succeeded on attempt {attempt} "
-                    f"(synapse recovered)",
+                    f"  [register] {username}: succeeded on attempt {attempt} (synapse recovered)",
                     flush=True,
                 )
             return r["body"] or {}
@@ -177,9 +176,9 @@ def test_register_two_users_send_receive_message(live_app):
     create + invite + join a room; send and read a message."""
     domain = live_app
     secret = _registration_secret(domain)
-    assert (
-        secret and len(secret) >= 16
-    ), f"registration shared secret missing/short: len={len(secret) if secret else 0}"
+    assert secret and len(secret) >= 16, (
+        f"registration shared secret missing/short: len={len(secret) if secret else 0}"
+    )
 
     suffix = uuid.uuid4().hex[:8]
     user_a = f"alice{suffix}"