feat: dashboard top hosts/types, problems 24h, drill-down (d2-2)

- Extend /dashboards/summary; Events filters from query (hostname, severity)

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/api/v1/dashboards.py

@@ -15,6 +15,17 @@ from app.services.host_health import DAILY_REPORT_SSH, HEARTBEAT_TYPE, count_sta
 router = APIRouter(prefix="/dashboards", tags=["dashboards"])
 
 
+class TopHostItem(BaseModel):
+    host_id: int
+    hostname: str
+    count: int
+
+
+class TopTypeItem(BaseModel):
+    type: str
+    count: int
+
+
 class DashboardSummary(BaseModel):
     events_last_24h: int
     hosts_total: int
@@ -22,7 +33,11 @@ class DashboardSummary(BaseModel):
     heartbeats_24h: int
     daily_reports_24h: int
     problems_open: int
+    problems_opened_24h: int
+    problems_resolved_24h: int
     severity_24h: dict[str, int]
+    top_hosts: list[TopHostItem]
+    top_event_types: list[TopTypeItem]
     recent_events: list[EventSummary]
 
 
@@ -52,6 +67,40 @@ def dashboard_summary(
     problems_open = (
         db.scalar(select(func.count()).select_from(Problem).where(Problem.status == "open")) or 0
     )
+    problems_opened_24h = (
+        db.scalar(select(func.count()).select_from(Problem).where(Problem.created_at >= since)) or 0
+    )
+    problems_resolved_24h = (
+        db.scalar(
+            select(func.count()).select_from(Problem).where(
+                Problem.status == "resolved",
+                Problem.updated_at >= since,
+            )
+        )
+        or 0
+    )
+
+    top_host_rows = db.execute(
+        select(Host.id, Host.hostname, func.count())
+        .select_from(Event)
+        .join(Host, Event.host_id == Host.id)
+        .where(Event.received_at >= since)
+        .group_by(Host.id, Host.hostname)
+        .order_by(func.count().desc())
+        .limit(10)
+    ).all()
+    top_hosts = [
+        TopHostItem(host_id=row[0], hostname=row[1], count=row[2]) for row in top_host_rows
+    ]
+
+    top_type_rows = db.execute(
+        select(Event.type, func.count())
+        .where(Event.received_at >= since)
+        .group_by(Event.type)
+        .order_by(func.count().desc())
+        .limit(10)
+    ).all()
+    top_event_types = [TopTypeItem(type=row[0], count=row[1]) for row in top_type_rows]
 
     severity_rows = db.execute(
         select(Event.severity, func.count())
@@ -92,6 +141,10 @@ def dashboard_summary(
         heartbeats_24h=heartbeats_24h,
         daily_reports_24h=daily_reports_24h,
         problems_open=problems_open,
+        problems_opened_24h=problems_opened_24h,
+        problems_resolved_24h=problems_resolved_24h,
         severity_24h=severity_24h,
+        top_hosts=top_hosts,
+        top_event_types=top_event_types,
         recent_events=recent_events,
     )