feat(dashboard): an Alerts widget beside the Overview; the Overview's overflow links to Alerts and Monitors (#5510)

The Alerts widget (/alerts/widget) is shaped like every widget: a verdict
("2 firing, 1 silent." / "Nothing firing: all 12 rules are quiet."), then
what is firing or silent with its reading now, what the rule fires on and
since when, then what someone acknowledged and who; a line when alert
email failed in the last 7 days or is retrying (outbox.alert_trouble),
linking admins to Settings -> System; the quiet rules counted, a covering
rule once. It sits beside the Overview in the recommended layout (6x4
each).

The Overview's "+N more" line pointed at the removed /status/; alerts now
link to /alerts/ and monitors to /monitors/.

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

steward/alerts/routes.py

@@ -178,6 +178,19 @@ async def active_fragment():
         rules_off=sum(1 for r in rules if not r.enabled))
 
 
+@alerts_bp.get("/widget")
+@require_role(UserRole.viewer)
+async def widget():
+    """The dashboard Alerts widget (#5510): a verdict, what is firing or
+    silent, then what someone has taken, a line when alert email is failing,
+    and the quiet rules counted."""
+    async with current_app.db_sessionmaker() as db:
+        active = await alert_svc.active_rows(db, datetime.now(timezone.utc))
+        view = alert_svc.widget_view(active, await alert_svc.list_rules(db))
+        email = await outbox.alert_trouble(db)
+    return await render_template("alerts/widget.html", **view, email=email)
+
+
 def _delivery(label: str, sent: bool | None, error: str | None) -> dict | None:
     """A channel's outcome as recorded on the event; None when not tried."""
     if sent is None:

steward/alerts/service.py

@@ -231,11 +231,13 @@ async def active_rows(db, now: datetime) -> list[dict]:
             since = started.get(rule.id, state.last_transition_at)
         else:
             since = state.last_transition_at
+        value = await latest_value(db, rule)
         rows.append({
             "state": state, "rule": rule, "label": label, "since": since,
             "breach_since": started.get(rule.id) if label != "no_data" else None,
             "acked_by": names.get(state.acknowledged_by, state.acknowledged_by),
-            "says": alert_sentence(rule, label, await latest_value(db, rule), since, now),
+            "value": value,
+            "says": alert_sentence(rule, label, value, since, now),
             "url": await resource_url(db, rule),
         })
     epoch = datetime.max.replace(tzinfo=timezone.utc)
@@ -243,6 +245,19 @@ async def active_rows(db, now: datetime) -> list[dict]:
     return rows
 
 
+def widget_view(active: list[dict], rules: list[AlertRule]) -> dict:
+    """The dashboard Alerts widget (#5510) from active_rows and every rule:
+    the alerts in that order, each with what its rule fires on, and how many
+    enabled rules, as people made them, are quiet (a covering rule counts
+    once, and is quiet only while every host under it is).
+    {"rows", "quiet", "total"}."""
+    busy = {r["rule"].id for r in active}
+    busy |= {r["rule"].parent_id for r in active if r["rule"].parent_id}
+    made = [r for r in rules if r.enabled and not r.parent_id]
+    return {"rows": [{**r, "condition": rule_condition(r["rule"])} for r in active],
+            "quiet": sum(1 for r in made if r.id not in busy), "total": len(made)}
+
+
 def watches_host(rule: AlertRule, host_name: str, monitor_keys: set) -> bool:
     """Whether a rule watches something on this host: its agent series
     ("<host>" or "<host>:<part>"), one of its containers ("<host>/<name>"),