feat: delete host from UI with events and problems cleanup

DELETE /api/v1/hosts/{id} (JWT); host reappears on next agent ingest

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

backend/app/api/v1/hosts.py

@@ -1,4 +1,5 @@
-from fastapi import APIRouter, Depends, Query
+from fastapi import APIRouter, Depends, HTTPException, Query
+from pydantic import BaseModel
 from sqlalchemy import func, select
 from sqlalchemy.orm import Session
 
@@ -7,6 +8,7 @@ from app.config import get_settings
 from app.database import get_db
 from app.models import Event, Host
 from app.schemas.list_models import HostListResponse, HostSummary
+from app.services.host_delete import delete_host_and_related
 from app.services.host_health import (
     HEARTBEAT_TYPE,
     agent_status,
@@ -75,3 +77,31 @@ def list_hosts(
         )
 
     return HostListResponse(items=items, total=total, page=page, page_size=page_size)
+
+
+class HostDeleteResponse(BaseModel):
+    status: str
+    host_id: int
+    hostname: str
+    deleted_events: int
+    deleted_problems: int
+
+
+@router.delete("/{host_id}", response_model=HostDeleteResponse)
+def delete_host(
+    host_id: int,
+    db: Session = Depends(get_db),
+    _user: str = Depends(get_current_user),
+) -> HostDeleteResponse:
+    result = delete_host_and_related(db, host_id)
+    if result is None:
+        raise HTTPException(status_code=404, detail="Host not found")
+    db.commit()
+    return HostDeleteResponse(
+        status="deleted",
+        host_id=result.host_id,
+        hostname=result.hostname,
+        deleted_events=result.deleted_events,
+        deleted_problems=result.deleted_problems,
+    )
+