Add clear host deletion controls with workload safeguards

src/lib/hosts.ts

@@ -2,6 +2,8 @@ export type HostMode = 'active' | 'draining' | 'disabled';
 export type HostReadiness = 'preparing' | 'ready' | 'degraded' | 'draining' | 'disabled';
 export type HostOperationState = 'pending' | 'accepted' | 'running' | 'completed' | 'failed' | 'unknown';
 
+export interface HostDeletion { allowed: boolean; blockers: string[] }
+
 export interface HostLibrary { id: string; state: 'missing' | 'downloading' | 'verifying' | 'ready' | 'failed' | 'outdated'; progress?: number; error?: string }
 export interface HostInventory {
     hostname?: string; agentVersion?: string; protocolVersion?: number; os?: string; architecture?: string;