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.

runner/harness/browser.py

@@ -13,8 +13,15 @@ from __future__ import annotations
 import time
 
 
-def goto_with_retry(page, url, *, deadline_seconds: int = 120, accept_statuses=(200, 304),
-                    goto_timeout_ms: int = 30_000, wait_until: str = "domcontentloaded"):
+def goto_with_retry(
+    page,
+    url,
+    *,
+    deadline_seconds: int = 120,
+    accept_statuses=(200, 304),
+    goto_timeout_ms: int = 30_000,
+    wait_until: str = "domcontentloaded",
+):
     """Poll `page.goto(url)` until status is in `accept_statuses` OR the deadline expires.
 
     Returns the final Playwright response. Raises AssertionError if the deadline expires without