Add config-sync cycle retention alongside config history keep.

Mirror LLDP job retention so finished sync cycles are pruned by policy while keeping per-NE config version history separate.

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

web/src/types.ts

@@ -670,6 +670,7 @@ export type ConfigSyncPolicy = {
   scope_mode: string;
   selected_targets: ConfigSyncTargetRef[];
   history_keep: number;
+  cycle_keep: number;
   updated_at?: string | null;
 };