test(service-automation): the plugin-node-type fixture's approval node carries the approvers its contract requires

registerFlow parses FlowSchema first, and the build doors now judge an
approval node's config against its declared contract, so the
vocabulary-seal fixture's contract-less approval node is refused before
the test reaches what it measures.

Claude-Session: https://claude.ai/code/session_01T9u38rswFp5Rw8DswRUReJ
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

packages/services/service-automation/src/engine.test.ts

@@ -2626,7 +2626,7 @@ describe('Action Descriptor Registry (ADR-0018)', () => {
         type: 'autolaunched' as const,
         nodes: [
             { id: 'start', type: 'start', label: 'Start' },
-            { id: 'custom', type, label: 'Custom' },
+            { id: 'custom', type, label: 'Custom', ...(type === 'approval' ? { config: { approvers: [{ type: 'user', value: 'u1' }] } } : {}) },
             { id: 'end', type: 'end', label: 'End' },
         ],
         edges: [