fix: graphSchema missing ON_SUCCESS edge type + label field

- Add all valid EdgeTypes to graphSchema.edges.type enum
- Add label field to graphSchema.nodes (graph-builder passes it)
- Was causing 圖定義產生失敗 for all /cypher/execute calls

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cypher-executor/src/lib/schemas.ts

@@ -8,12 +8,13 @@ export const graphSchema = z.object({
     id: z.string(),
     type: z.enum(['Input', 'Component', 'Output']),
     componentId: z.string().optional(),
+    label: z.string().optional(),
     data: z.record(z.unknown()).optional(),
   })),
   edges: z.array(z.object({
     from: z.string(),
     to: z.string(),
-    type: z.enum(['PIPE', 'IF', 'FOREACH', 'CONTINUE']),
+    type: z.enum(['PIPE', 'IF', 'FOREACH', 'CONTINUE', 'IS_A', 'ON_SUCCESS', 'ON_FAIL', 'ON_CLICK', 'CALLS_SUBFLOW', 'CONTAINS', 'HAS_STYLE', 'HAS_BEHAVIOR']),
     condition: z.string().optional(),
     iterator: z.string().optional(),
   })),