style: repo-wide lint pass — make the lint gate green again

Push builds have been RED on the lint step since ~build 209 from accumulated
formatting drift. This is the mechanical cleanup: ruff format + ruff --fix
(UP038 isinstance unions, SIM105 contextlib.suppress, UP031 f-strings, SIM115
tempfile context manager), shfmt -i 2 -ci, nixpkgs-fmt/statix/deadnix (merged
attrsets, dropped unused lib args), yamllint, and shell quoting fixes in
tests/lasuite-docs/setup_custom_tests.sh. No behaviour changes intended;
lint: PASS, unit tests: 138 passed.

tests/mattermost-lts/functional/test_create_message.py

@@ -41,9 +41,9 @@ def test_create_message_roundtrip(live_app):
         headers=auth,
         timeout=30,
     )
-    assert status in (200, 201) and isinstance(team, dict) and team.get("id"), (
-        f"team creation failed: HTTP {status}, body={team!r}"
-    )
+    assert (
+        status in (200, 201) and isinstance(team, dict) and team.get("id")
+    ), f"team creation failed: HTTP {status}, body={team!r}"
     status, chan = harness_http.http_post(
         f"{base}/channels",
         data={
@@ -55,9 +55,9 @@ def test_create_message_roundtrip(live_app):
         headers=auth,
         timeout=30,
     )
-    assert status in (200, 201) and isinstance(chan, dict) and chan.get("id"), (
-        f"channel creation failed: HTTP {status}, body={chan!r}"
-    )
+    assert (
+        status in (200, 201) and isinstance(chan, dict) and chan.get("id")
+    ), f"channel creation failed: HTTP {status}, body={chan!r}"
 
     # 4) POST a unique marker message.
     marker = f"ccci-marker-{uniq}-roundtrip"
@@ -67,13 +67,13 @@ def test_create_message_roundtrip(live_app):
         headers=auth,
         timeout=30,
     )
-    assert status in (200, 201) and isinstance(post, dict) and post.get("id"), (
-        f"post creation failed: HTTP {status}, body={post!r}"
-    )
+    assert (
+        status in (200, 201) and isinstance(post, dict) and post.get("id")
+    ), f"post creation failed: HTTP {status}, body={post!r}"
 
     # 5) Read it back by id and assert the message survived the round-trip.
     status, got = harness_http.http_get(f"{base}/posts/{post['id']}", headers=auth, timeout=30)
     assert status == 200 and isinstance(got, dict), f"read-back failed: HTTP {status}, body={got!r}"
-    assert got.get("message") == marker, (
-        f"message did not round-trip: sent {marker!r}, got {got.get('message')!r}"
-    )
+    assert (
+        got.get("message") == marker
+    ), f"message did not round-trip: sent {marker!r}, got {got.get('message')!r}"

tests/mattermost-lts/functional/test_health_check.py

@@ -18,9 +18,7 @@ from harness import http as harness_http  # noqa: E402
 def test_root_serves(live_app):
     """GET / → 200 or 302 (mattermost web app shell / login redirect)."""
     url = f"https://{live_app}/"
-    status, _ = harness_http.retry_http_get(
-        url, expect_status=(200, 302), max_wait=60, interval=3
-    )
+    status, _ = harness_http.retry_http_get(url, expect_status=(200, 302), max_wait=60, interval=3)
     assert status in (200, 302), f"GET {url} HTTP {status} (expected 200/302)"
 
 
@@ -28,10 +26,8 @@ def test_system_ping_ok(live_app):
     """GET /api/v4/system/ping → 200 with JSON {"status":"OK"} — the mattermost server's own
     liveness endpoint (distinguishes a live mattermost API from a Traefik fallback / dead backend)."""
     url = f"https://{live_app}/api/v4/system/ping"
-    status, body = harness_http.retry_http_get(
-        url, expect_status=200, max_wait=120, interval=3
-    )
+    status, body = harness_http.retry_http_get(url, expect_status=200, max_wait=120, interval=3)
     assert status == 200, f"GET {url} HTTP {status} (expected 200)"
-    assert isinstance(body, dict) and body.get("status") == "OK", (
-        f"/api/v4/system/ping did not report status=OK; got {body!r}"
-    )
+    assert (
+        isinstance(body, dict) and body.get("status") == "OK"
+    ), f"/api/v4/system/ping did not report status=OK; got {body!r}"

tests/mattermost-lts/functional/test_multiuser_message.py

@@ -51,7 +51,12 @@ def test_second_user_reads_first_users_message(live_app):
     assert status in (200, 201) and team.get("id"), f"team create HTTP {status}: {team!r}"
     status, chan = harness_http.http_post(
         f"{base}/channels",
-        data={"team_id": team["id"], "name": f"c{uniq}", "display_name": f"chan {uniq}", "type": "O"},
+        data={
+            "team_id": team["id"],
+            "name": f"c{uniq}",
+            "display_name": f"chan {uniq}",
+            "type": "O",
+        },
         headers=auth_a,
         timeout=30,
     )
@@ -60,7 +65,10 @@ def test_second_user_reads_first_users_message(live_app):
     # 2) user_a posts a unique marker
     marker = f"ccci-multiuser-{uniq}"
     status, post = harness_http.http_post(
-        f"{base}/posts", data={"channel_id": chan["id"], "message": marker}, headers=auth_a, timeout=30
+        f"{base}/posts",
+        data={"channel_id": chan["id"], "message": marker},
+        headers=auth_a,
+        timeout=30,
     )
     assert status in (200, 201) and post.get("id"), f"post create HTTP {status}: {post!r}"
 
@@ -97,6 +105,6 @@ def test_second_user_reads_first_users_message(live_app):
 
     # 5) user_b sees user_a's marker (cross-user delivery, not a self read-back)
     messages = [p.get("message") for p in (posts.get("posts") or {}).values()]
-    assert marker in messages, (
-        f"user_b did not see user_a's message {marker!r} in the channel; saw {messages!r}"
-    )
+    assert (
+        marker in messages
+    ), f"user_b did not see user_a's message {marker!r} in the channel; saw {messages!r}"