Add clear host deletion controls with workload safeguards

src/lib/server/hosts/schema.ts

@@ -10,7 +10,7 @@ export function ensureHostSchema(handle: Database.Database): void {
             port_min INTEGER NOT NULL DEFAULT 28960, port_max INTEGER NOT NULL DEFAULT 28980,
             bind_address TEXT NOT NULL DEFAULT '0.0.0.0', public_address TEXT NOT NULL DEFAULT '',
             minimum_free_bytes INTEGER NOT NULL DEFAULT 1073741824,
-            created_at TEXT NOT NULL, enrolled_at TEXT, last_heartbeat TEXT, inventory TEXT NOT NULL DEFAULT '{}'
+            created_at TEXT NOT NULL, enrolled_at TEXT, last_heartbeat TEXT, inventory TEXT NOT NULL DEFAULT '{}', deleted_at TEXT
         );
         CREATE TABLE IF NOT EXISTS ec_host_enrollments (
             id TEXT PRIMARY KEY, host_id TEXT NOT NULL REFERENCES ec_hosts(id), token_hash TEXT NOT NULL UNIQUE,
@@ -43,5 +43,7 @@ export function ensureHostSchema(handle: Database.Database): void {
     `);
     const columns = handle.prepare('PRAGMA table_info(ec_host_operations)').all() as { name: string }[];
     if (!columns.some(column => column.name === 'last_delivered_at')) handle.exec('ALTER TABLE ec_host_operations ADD COLUMN last_delivered_at TEXT');
+    const hostColumns = handle.prepare('PRAGMA table_info(ec_hosts)').all() as { name: string }[];
+    if (!hostColumns.some(column => column.name === 'deleted_at')) handle.exec('ALTER TABLE ec_hosts ADD COLUMN deleted_at TEXT');
     initialized.add(handle);
 }