feat: implement webhook path autofixer and improve node similarity service

- Add webhook path auto-generation for nodes missing path configuration
  - Generates UUID for both 'path' parameter and 'webhookId' field
  - Conditionally updates typeVersion to 2.1 only when < 2.1
  - High confidence fix (95%) as UUID generation is deterministic

- Fix critical security and performance issues in NodeSimilarityService:
  - Replace regex patterns with string-based matching to prevent ReDoS attacks
  - Add cache invalidation with version tracking to prevent memory leaks
  - Optimize Levenshtein distance algorithm from O(m*n) space to O(n)
  - Add early termination for performance improvement
  - Extract magic numbers into named constants

- Add comprehensive documentation for n8n_autofix_workflow tool
  - Document all fix types including new webhook-missing-path
  - Include examples, best practices, and warnings
  - Integrate with MCP tool documentation system

- Create node-type-utils for centralized type normalization
  - Eliminate code duplication across services
  - Consistent handling of package prefixes

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

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

src/mcp/tools-n8n-manager.ts

@@ -270,6 +270,41 @@ export const n8nManagementTools: ToolDefinition[] = [
       required: ['id']
     }
   },
+  {
+    name: 'n8n_autofix_workflow',
+    description: `Automatically fix common workflow validation errors. Preview fixes or apply them. Fixes expression format, typeVersion, error output config, webhook paths.`,
+    inputSchema: {
+      type: 'object',
+      properties: {
+        id: {
+          type: 'string',
+          description: 'Workflow ID to fix'
+        },
+        applyFixes: {
+          type: 'boolean',
+          description: 'Apply fixes to workflow (default: false - preview mode)'
+        },
+        fixTypes: {
+          type: 'array',
+          description: 'Types of fixes to apply (default: all)',
+          items: {
+            type: 'string',
+            enum: ['expression-format', 'typeversion-correction', 'error-output-config', 'node-type-correction', 'webhook-missing-path']
+          }
+        },
+        confidenceThreshold: {
+          type: 'string',
+          enum: ['high', 'medium', 'low'],
+          description: 'Minimum confidence level for fixes (default: medium)'
+        },
+        maxFixes: {
+          type: 'number',
+          description: 'Maximum number of fixes to apply (default: 50)'
+        }
+      },
+      required: ['id']
+    }
+  },
 
   // Execution Management Tools
   {