fix: cleanup stale references and update tests after tool removal

- Remove handleListAvailableTools dead code from handlers-n8n-manager.ts
- Update error messages to reference n8n_health_check(mode="diagnostic") instead of n8n_diagnostic
- Update tool counts in diagnostic messages (14 doc tools, 31 total)
- Fix error-handling.test.ts to use valid tools (search_nodes, tools_documentation)
- Remove obsolete list-tools.test.ts integration tests
- Remove unused ListToolsResponse type from response-types.ts
- Update tools.ts QUICK REFERENCE to remove list_nodes references
- Update tools-documentation.ts to remove references to removed tools
- Update tool-docs files to remove stale relatedTools references
- Fix tools.test.ts to not test removed tools (list_nodes, list_ai_tools, etc.)
- Fix parameter-validation.test.ts to not test removed tools
- Update handlers-n8n-manager.test.ts error message expectations

All 399 MCP unit tests now pass.

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

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

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

tests/integration/n8n-api/utils/response-types.ts

@@ -19,29 +19,6 @@ export interface HealthCheckResponse {
   [key: string]: any; // Allow dynamic property access for optional field checks
 }
 
-export interface ToolDefinition {
-  name: string;
-  description: string;
-}
-
-export interface ToolCategory {
-  category: string;
-  tools: ToolDefinition[];
-}
-
-export interface ApiConfiguration {
-  apiUrl: string;
-  timeout: number;
-  maxRetries: number;
-}
-
-export interface ListToolsResponse {
-  tools: ToolCategory[];
-  apiConfigured: boolean;
-  configuration?: ApiConfiguration | null;
-  limitations: string[];
-}
-
 export interface ApiStatus {
   configured: boolean;
   connected: boolean;