fix: resolve TypeScript errors in test files

- Add type assertions for factory options arrays
- Add 'this' type annotations to mock functions
- Fix missing required properties in test objects
- Change Mock to MockInstance for Vitest compatibility
- Add non-null assertions where needed

All 943 tests now passing

tests/unit/mcp/tools.test.ts

@@ -287,7 +287,7 @@ describe('n8nDocumentationToolsFinal', () => {
       );
 
       toolsWithRequired.forEach(tool => {
-        tool.inputSchema.required.forEach(requiredParam => {
+        tool.inputSchema.required!.forEach(requiredParam => {
           expect(tool.inputSchema.properties).toHaveProperty(requiredParam);
         });
       });