Add version-aware settings filtering for n8n API compatibility

This commit adds automatic detection of n8n server version and filters
workflow settings properties based on what the target version supports.

Changes:
- Add n8n-version.ts service for version detection via /rest/settings
- Fix nested response structure handling (data.data.versionCli)
- Add N8nVersionInfo and N8nSettingsData types
- Update N8nApiClient with getVersion() and version-aware filtering
- Clean workflow settings before API update based on detected version

Version compatibility:
- n8n < 1.37.0: 7 core properties only
- n8n 1.37.0+: adds executionOrder
- n8n 1.119.0+: adds callerPolicy, callerIds, timeSavedPerExecution, availableInMCP

Fixes #466

src/types/n8n-api.ts

@@ -225,6 +225,28 @@ export interface HealthCheckResponse {
   };
 }
 
+// n8n Version Information
+export interface N8nVersionInfo {
+  version: string;          // Full version string, e.g., "1.119.0"
+  major: number;            // Major version number
+  minor: number;            // Minor version number
+  patch: number;            // Patch version number
+}
+
+// Settings data within the response
+export interface N8nSettingsData {
+  n8nVersion?: string;
+  versionCli?: string;
+  instanceId?: string;
+  [key: string]: unknown;
+}
+
+// Response from /rest/settings endpoint (unauthenticated)
+// The actual response wraps settings in a "data" property
+export interface N8nSettingsResponse {
+  data?: N8nSettingsData;
+}
+
 // Request Parameter Types
 export interface WorkflowListParams {
   limit?: number;