Add cancellation and cleanup for native server creation

src/lib/server/hosts/index.ts

@@ -288,6 +288,11 @@ type OperationRow = { id: string; host_id: string; kind: string; instance_id: st
 function operationFromRow(row: OperationRow): HostOperation { return { id: row.id, hostId: row.host_id, kind: row.kind, instanceId: row.instance_id, generation: row.generation, payload: JSON.parse(row.payload), state: row.state, result: row.result === null ? null : JSON.parse(row.result), error: row.error, createdAt: row.created_at, updatedAt: row.updated_at }; }
 export function getHostOperation(id: string): HostOperation | null { const row = database().prepare('SELECT * FROM ec_host_operations WHERE id=?').get(id) as OperationRow | undefined; return row ? operationFromRow(row) : null; }
 export function listHostOperations(hostId: string, limit = 100): HostOperation[] { return (database().prepare('SELECT * FROM ec_host_operations WHERE host_id=? ORDER BY created_at DESC,rowid DESC LIMIT ?').all(hostId, Math.min(500, Math.max(1, limit))) as OperationRow[]).map(operationFromRow); }
+/** Heartbeats can tell an executing create to stop at its next safe command boundary. */
+export function pendingCreationCancellations(hostId: string): string[] {
+    return (database().prepare(`SELECT json_extract(payload,'$.createOperationId') AS id FROM ec_host_operations
+        WHERE host_id=? AND kind='instance.cancel-create' AND state IN ('pending','accepted','running','unknown')`).all(hostId) as { id: string }[]).map(row => row.id);
+}
 export function queueHostOperation(hostId: string, kind: string, payload: Record<string, unknown>, options: { instanceId?: string; generation?: number; idempotencyKey?: string; id?: string } = {}): HostOperation {
     const host = requireHost(hostId);
     if (host.decommission) throw new Error('Host cleanup is in progress; new operations are blocked.');
@@ -304,7 +309,7 @@ export function queueHostOperation(hostId: string, kind: string, payload: Record
             }
         }
         if (['instance.create','create'].includes(kind)) requireReadyHost(hostId);
-        if (host.mode === 'disabled') throw new Error('Host is disabled. Enable it before requesting operations.');
+        if (host.mode === 'disabled' && kind !== 'instance.cancel-create') throw new Error('Host is disabled. Enable it before requesting operations.');
         const id = options.id ?? randomUUID(); const timestamp = now();
         database().prepare('INSERT INTO ec_host_operations(id,host_id,kind,instance_id,generation,idempotency_key,payload,created_at,updated_at) VALUES(?,?,?,?,?,?,?,?,?)').run(id, hostId, kind, options.instanceId ?? null, options.generation ?? null, options.idempotencyKey ?? null, JSON.stringify(payload), timestamp, timestamp);
         database().prepare('INSERT INTO ec_host_operation_events(operation_id,state,created_at) VALUES(?,?,?)').run(id, 'pending', timestamp);
@@ -317,9 +322,13 @@ export function pendingHostOperations(hostId: string): HostOperation[] {
     // Accepted/running/unknown commands keep the same immutable ID. The agent
     // consults its durable journal before acknowledging or executing a replay.
     return database().transaction(() => {
-        const rows = database().prepare(`SELECT * FROM ec_host_operations WHERE host_id=? AND state IN ('pending','accepted','running','unknown')
+        const rows = database().prepare(`SELECT * FROM ec_host_operations o WHERE host_id=? AND state IN ('pending','accepted','running','unknown')
             AND (? OR state != 'pending' OR kind NOT IN ('instance.create','create'))
-            ORDER BY COALESCE(last_delivered_at,''),created_at,rowid LIMIT 25`).all(hostId, Number(host.readiness === 'ready')) as OperationRow[];
+            AND (kind!='instance.cancel-create' OR ?)
+            AND NOT EXISTS (SELECT 1 FROM ec_host_operations cancellation WHERE cancellation.host_id=o.host_id
+                AND cancellation.kind='instance.cancel-create' AND json_extract(cancellation.payload,'$.createOperationId')=o.id)
+            ORDER BY CASE WHEN kind='instance.cancel-create' THEN 0 ELSE 1 END,COALESCE(last_delivered_at,''),created_at,rowid LIMIT 25`)
+            .all(hostId, Number(host.readiness === 'ready'), Number(host.inventory.capabilities?.includes('instance.cancel-create') ?? false)) as OperationRow[];
         const deliveredAt = now();
         for (const operation of rows) database().prepare('UPDATE ec_host_operations SET last_delivered_at=? WHERE id=?').run(deliveredAt, operation.id);
         return rows.map(operationFromRow);