feat(ui): audit, alert rules and the rule form say things in words (#5212)

#5212 "Plain labels: no raw ids, scopes, metric keys or unexplained jargon",
batch 1:

- Audit log: each action reads as a sentence ("paused monitor"), with the
  code as its tooltip. Detail shows flags as yes/no, lists joined, a run's
  scope by name, spans as spans, and no ids the entity column already gives.
  The filter is now a picker of areas.
- Alert rules, history and Status say the condition in words: "is down",
  "Fullest disk >= 85%". Readings use metric_value, and history times use
  |ago.
- Rule form: sources and metrics by name, the threshold's unit, "fires
  when it is down/up" for an up/down metric instead of 0.5, and a metric
  reference built from the catalog.
- Schedules and Maintenance: viewers no longer see Run now, Pause, Edit,
  Delete or New. Intervals and next runs read as "every 2h" and "in 3h";
  a scope reads "Every alert on Host agent".

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

tests/integration/test_alert_history_page.py

@@ -68,9 +68,9 @@ def test_a_viewer_reads_the_alert_history(app):
         page = await resp.get_data(as_text=True)
         assert "Alert History" in page and 'href="/alerts/"' in page  # crumbs back to Alerts
         assert f"hot {tag}" in page and f"cold-note-{tag}" in page and f"old-{tag}" not in page
-        assert "cpu_pct = 97.5" in page and "rule: > 90" in page
+        assert "CPU 98%" in page and "fires when CPU > 90%" in page
         assert "email failed" in page and f"mx-{tag}: timed out" in page and "webhook sent" in page
-        assert f"muted · patch-{tag}" in page and "cpu_pct = no data" in page
+        assert f"muted · patch-{tag}" in page and "No CPU reading" in page
 
         resp = await client.get(f"/alerts/history?range=24h&rule={hot_id}", headers={"HX-Request": "true"})
         rows = await resp.get_data(as_text=True)
@@ -84,7 +84,7 @@ def test_a_viewer_reads_the_alert_history(app):
             "range": "24h", "rule": hot_id, "before": cursor(now - timedelta(minutes=3), "")})
         older = await resp.get_data(as_text=True)
         assert resp.status_code == 200 and "<table" not in older
-        assert "cpu_pct = 97.5" in older and f"old-{tag}" in older and f"patch-{tag}" not in older
+        assert "CPU 98%" in older and f"old-{tag}" in older and f"patch-{tag}" not in older
         assert "End of the list." in older and "data-scroll-more" not in older
 
         # The rules list links each rule to its history.