Fix code review issues: use proper Zod type inference instead of private internals

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot

packages/spec/src/system/api.test.ts

@@ -186,7 +186,7 @@ describe('ApiEndpointSchema', () => {
   });
 
   it('should accept different HTTP methods', () => {
-    const methods: Array<typeof HttpMethod._type> = ['GET', 'POST', 'PUT', 'DELETE', 'PATCH'];
+    const methods: Array<z.infer<typeof HttpMethod>> = ['GET', 'POST', 'PUT', 'DELETE', 'PATCH'];
 
     methods.forEach(method => {
       const endpoint = ApiEndpointSchema.parse({
@@ -201,7 +201,7 @@ describe('ApiEndpointSchema', () => {
   });
 
   it('should accept different implementation types', () => {
-    const types: Array<typeof endpoint.type> = ['flow', 'script', 'object_operation', 'proxy'];
+    const types: Array<'flow' | 'script' | 'object_operation' | 'proxy'> = ['flow', 'script', 'object_operation', 'proxy'];
 
     types.forEach(type => {
       const endpoint = ApiEndpointSchema.parse({
@@ -257,7 +257,7 @@ describe('ApiEndpointSchema', () => {
   });
 
   it('should accept different object operations', () => {
-    const operations: Array<NonNullable<NonNullable<typeof endpoint.objectParams>['operation']>> = ['find', 'get', 'create', 'update', 'delete'];
+    const operations: Array<'find' | 'get' | 'create' | 'update' | 'delete'> = ['find', 'get', 'create', 'update', 'delete'];
 
     operations.forEach(operation => {
       const endpoint = ApiEndpointSchema.parse({

packages/spec/src/ui/report.test.ts

@@ -254,7 +254,7 @@ describe('ReportSchema', () => {
   });
 
   it('should accept different report types', () => {
-    const types: Array<typeof ReportType._type> = ['tabular', 'summary', 'matrix', 'joined'];
+    const types: Array<z.infer<typeof ReportType>> = ['tabular', 'summary', 'matrix', 'joined'];
 
     types.forEach(type => {
       const report = ReportSchema.parse({