fix: harden _cnd operators and add edge case tests

- Add try/catch for invalid regex patterns in regex operator
- Add structure validation for between operator (from/to fields)
- Add 5 new edge case tests for invalid inputs
- Bump version to 2.30.1
- Resolve merge conflict with main (n8n 2.0 update)

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/unit/services/config-validator-cnd.test.ts

@@ -216,6 +216,36 @@ describe('ConfigValidator _cnd operators', () => {
         };
         expect(ConfigValidator.isPropertyVisible(prop, { '@version': 5 })).toBe(false);
       });
+
+      it('should not match when between structure is null', () => {
+        const prop = {
+          name: 'testField',
+          displayOptions: {
+            show: { '@version': [{ _cnd: { between: null } }] }
+          }
+        };
+        expect(ConfigValidator.isPropertyVisible(prop, { '@version': 4 })).toBe(false);
+      });
+
+      it('should not match when between is missing from field', () => {
+        const prop = {
+          name: 'testField',
+          displayOptions: {
+            show: { '@version': [{ _cnd: { between: { to: 5 } } }] }
+          }
+        };
+        expect(ConfigValidator.isPropertyVisible(prop, { '@version': 4 })).toBe(false);
+      });
+
+      it('should not match when between is missing to field', () => {
+        const prop = {
+          name: 'testField',
+          displayOptions: {
+            show: { '@version': [{ _cnd: { between: { from: 3 } } }] }
+          }
+        };
+        expect(ConfigValidator.isPropertyVisible(prop, { '@version': 4 })).toBe(false);
+      });
     });
 
     describe('startsWith operator', () => {
@@ -314,6 +344,27 @@ describe('ConfigValidator _cnd operators', () => {
         };
         expect(ConfigValidator.isPropertyVisible(prop, { id: 'abc1234' })).toBe(false);
       });
+
+      it('should not match when regex pattern is invalid', () => {
+        const prop = {
+          name: 'testField',
+          displayOptions: {
+            show: { id: [{ _cnd: { regex: '[invalid(regex' } }] }
+          }
+        };
+        // Invalid regex should return false without throwing
+        expect(ConfigValidator.isPropertyVisible(prop, { id: 'test' })).toBe(false);
+      });
+
+      it('should not match non-string values', () => {
+        const prop = {
+          name: 'testField',
+          displayOptions: {
+            show: { value: [{ _cnd: { regex: '\\d+' } }] }
+          }
+        };
+        expect(ConfigValidator.isPropertyVisible(prop, { value: 123 })).toBe(false);
+      });
     });
 
     describe('exists operator', () => {