feat(alerts): history reads as episodes; tests follow the confirm dialog (#5316, #5314)

History (#5316):
- Transitions fold into episodes (steward/alerts/episodes.py): each stretch
  out of quiet, the worst state it reached, how long it lasted, its worst
  reading against the rule ('3m 21s (fires above 3m)'), who was told across
  its changes, and its Ansible runs. The changes themselves fold under it.
- An episode cut by paging says so ('cleared later (above)', 'earlier').
- For one rule: a verdict ('Fired 4 times in the last 7d, 1h 2m in all') and
  no Rule column. Notified and Action show only when the range has any.

Tests:
- The confirm guard looks for a confirm( call, not the word in the comment
  that says it is gone (lesson #4365).
- The Hosts viewer test looks for the add-host dialog by id, since every page
  now carries the confirm dialog.

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

tests/test_inline_handlers.py

@@ -47,5 +47,5 @@ def test_base_asks_before_a_data_confirm_form_submits():
     assert re.search(r'<button type="submit"[^>]*btn-danger[^>]*value="go"', base)
     assert "dataset.confirm" in js and "getElementById('confirm-dialog')" in js and "requestSubmit" in js
     assert "textContent = title" in js and "innerHTML" not in js                         # text, never markup
-    assert "window.confirm" not in js and "window.confirm" not in base
+    assert not re.search(r"\bconfirm\s*\(", js + base)       # a call, not the comment saying it is gone
     assert any("data-confirm=" in p.read_text() for p in _templates())