fix(ui): delete prompts use data-confirm, so a quote in a name no longer runs script (#5099)

#5099 "A name containing a quote runs script when an admin clicks Delete".
Inline handlers like onclick="return confirm('Delete {{ rule.name }}?')" are
HTML-decoded before the JavaScript is parsed, so autoescaping did not stop a
name such as  x');fetch(…);//  from running.

- Every prompt (22 handlers, plus the docker prune and token revoke ones)
  is now data-confirm="…", read through dataset by one submit listener in
  base.html; nothing rendered is parsed as JavaScript.
- The remaining inline handlers take integers only (|int), and the time
  range buttons pass this.dataset.range.
- tests/test_inline_handlers.py fails on any {{ }} in an inline handler that
  is not |int, with a self-test; tests/_templates.py is the one template
  walker the template guards now share.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/_templates.py

@@ -0,0 +1,12 @@
+"""Where Steward's templates live, for the guards that read every one."""
+import pathlib
+
+import steward
+
+REPO = pathlib.Path(steward.__file__).parent.parent
+
+
+def template_files() -> list[pathlib.Path]:
+    """Every first-party .html template: core and each plugin's."""
+    roots = [REPO / "steward" / "templates", *(REPO / "plugins").glob("*/templates")]
+    return sorted(p for root in roots for p in root.rglob("*.html"))