feat: Add constraint management API and configuration

- Add constraint-management feature to features.json
- Create /api/admin/constraints endpoint (GET, POST, DELETE)
- Support UNIQUE and CHECK constraints
- Add getConstraintTypes() utility function
- Add integration tests for constraints API
- Add unit tests for constraint types
- Follow CODE_STYLE.md guidelines

Co-authored-by: johndoe6345789 <224850594+johndoe6345789@users.noreply.github.com>

src/utils/featureConfig.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from 'vitest';
 import {
+  getConstraintTypes,
   getDataTypes,
   getEnabledFeaturesByPriority,
   getFeatureById,
@@ -257,6 +258,47 @@ describe('FeatureConfig', () => {
     });
   });
 
+  describe('getConstraintTypes', () => {
+    it('should return array of constraint types', () => {
+      const constraintTypes = getConstraintTypes();
+      
+      expect(Array.isArray(constraintTypes)).toBe(true);
+    });
+
+    it('should return constraint types with required properties', () => {
+      const constraintTypes = getConstraintTypes();
+      
+      constraintTypes.forEach(constraintType => {
+        expect(constraintType).toHaveProperty('name');
+        expect(constraintType).toHaveProperty('description');
+        expect(constraintType).toHaveProperty('requiresColumn');
+        expect(constraintType).toHaveProperty('requiresExpression');
+        expect(typeof constraintType.name).toBe('string');
+        expect(typeof constraintType.description).toBe('string');
+        expect(typeof constraintType.requiresColumn).toBe('boolean');
+        expect(typeof constraintType.requiresExpression).toBe('boolean');
+      });
+    });
+
+    it('should include UNIQUE constraint type', () => {
+      const constraintTypes = getConstraintTypes();
+      const uniqueConstraint = constraintTypes.find(ct => ct.name === 'UNIQUE');
+      
+      expect(uniqueConstraint).toBeDefined();
+      expect(uniqueConstraint?.requiresColumn).toBe(true);
+      expect(uniqueConstraint?.requiresExpression).toBe(false);
+    });
+
+    it('should include CHECK constraint type', () => {
+      const constraintTypes = getConstraintTypes();
+      const checkConstraint = constraintTypes.find(ct => ct.name === 'CHECK');
+      
+      expect(checkConstraint).toBeDefined();
+      expect(checkConstraint?.requiresColumn).toBe(false);
+      expect(checkConstraint?.requiresExpression).toBe(true);
+    });
+  });
+
   describe('Feature endpoints', () => {
     it('should have valid endpoint structure for database-crud', () => {
       const feature = getFeatureById('database-crud');

src/utils/featureConfig.ts

@@ -33,6 +33,13 @@ export type NavItem = {
   featureId: string;
 };
 
+export type ConstraintType = {
+  name: string;
+  description: string;
+  requiresColumn: boolean;
+  requiresExpression: boolean;
+};
+
 export function getFeatures(): Feature[] {
   return featuresConfig.features.filter(f => f.enabled);
 }
@@ -45,6 +52,10 @@ export function getDataTypes(): DataType[] {
   return featuresConfig.dataTypes;
 }
 
+export function getConstraintTypes(): ConstraintType[] {
+  return (featuresConfig as any).constraintTypes || [];
+}
+
 export function getNavItems(): NavItem[] {
   return featuresConfig.navItems.filter(item => {
     const feature = getFeatureById(item.featureId);