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>

steward/app.py

@@ -145,6 +145,11 @@ def create_app(
     # The status and layout macros in _macros.html read these.
     app.jinja_env.globals["status_info"] = _fmt.status_info
     app.jinja_env.globals["required"] = _fmt.required
+    # A metric and its source in words, a reading in its unit (alerts pages).
+    for _name in ("metric_label", "metric_about", "metric_unit", "metric_value", "source_label"):
+        app.jinja_env.globals[_name] = getattr(_fmt, _name)
+    from .alerts.service import rule_condition as _rule_condition
+    app.jinja_env.globals["rule_condition"] = _rule_condition
     from .models.monitors import MONITOR_TYPE_LABELS as _type_labels
     app.jinja_env.filters["monitor_type"] = lambda t: _type_labels.get(t, str(t).upper())