feat(ui): audit log, alert history and Ansible runs load as you scroll (#5211)

#5211 "Lists load as you scroll: audit, alert history, Ansible runs"
(milestone 477), per preference 172.

- core/paging.py: keyset paging over (time, id), newest first, with an
  opaque "<iso>|<id>" cursor; a page reads one row past itself to know
  whether another follows. No OFFSET, so rows added while someone scrolls
  never shift the pages after them.
- _macros.html scroll_more / scroll_end and static/scroll-more.js, written
  once: an IntersectionObserver with a 600px margin fetches the next page
  before the reader reaches the end; "Loading more…" while in flight,
  "End of the list." at the end, and a failed page says so with a Retry
  button instead of re-firing on every scroll.
- Audit log: no "Load more" link and no 500-row cap.
- Alert history: no 200-row stop with "pick a shorter range";
  alert_svc.history takes the cursor, so the MCP tool and the page share
  one query.
- Ansible runs: no silent cap of 50.

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

tests/core/test_audit_page.py

@@ -39,7 +39,20 @@ async def test_the_page_names_and_links_the_entity(app):
          "entity": {"label": "api check", "url": None, "gone": True}},
     ]
     async with app.test_request_context("/audit/"):
-        page = await render_template("audit/list.html", events=events, limit=200, action_filter="")
+        page = await render_template("audit/list.html", events=events, after=None, action_filter="")
     assert '<a href="/hosts/h1">web-1</a>' in page
     assert "api check" in page and "(deleted)" in page
     assert "h1</td>" not in page  # no bare id where a name is known
+
+
+
+async def test_the_log_continues_itself_instead_of_a_load_more_link(app):
+    events = [{"event": _ev("host", "h1", "host.renamed"), "detail": {}, "entity": None}]
+    async with app.test_request_context("/audit/"):
+        more = await render_template("audit/list.html", events=events,
+                                     after="2026-10-07T03:00:00+00:00|0190abc", action_filter="host.")
+        last = await render_template("audit/_rows.html", events=events, after=None, action_filter="")
+    assert ('data-scroll-more hx-get="/audit/?before=2026-10-07T03%3A00%3A00%2B00%3A00%7C0190abc'
+            '&amp;action=host."') in more
+    assert "Load more" not in more
+    assert "data-scroll-more" not in last and "End of the list." in last