chore: update n8n to 2.1.4 and bump version to 2.31.2 (#507)

- Updated n8n from 2.0.2 to 2.1.4
- Updated n8n-core from 2.0.1 to 2.1.3
- Updated n8n-workflow from 2.0.1 to 2.1.1
- Updated @n8n/n8n-nodes-langchain from 2.0.1 to 2.1.3
- Rebuilt node database with 540 nodes (434 from n8n-nodes-base, 106 from @n8n/n8n-nodes-langchain)
- Refreshed template database with 2,737 workflow templates from n8n.io
- Updated README badge with new n8n version
- Updated CHANGELOG with dependency changes

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

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

Co-authored-by: Romuald Członkowski <romualdczlonkowski@MacBook-Pro-Romuald.local>
Co-authored-by: Claude <noreply@anthropic.com>

dist/mcp/tools-n8n-manager.js

@@ -336,8 +336,8 @@ exports.n8nManagementTools = [
                 },
                 mode: {
                     type: 'string',
-                    enum: ['preview', 'summary', 'filtered', 'full'],
-                    description: 'For action=get: preview=structure only, summary=2 items (default), filtered=custom, full=all data'
+                    enum: ['preview', 'summary', 'filtered', 'full', 'error'],
+                    description: 'For action=get: preview=structure only, summary=2 items (default), filtered=custom, full=all data, error=optimized error debugging'
                 },
                 nodeNames: {
                     type: 'array',
@@ -352,6 +352,22 @@ exports.n8nManagementTools = [
                     type: 'boolean',
                     description: 'For action=get: include input data in addition to output (default: false)'
                 },
+                errorItemsLimit: {
+                    type: 'number',
+                    description: 'For action=get with mode=error: sample items from upstream node (default: 2, max: 100)'
+                },
+                includeStackTrace: {
+                    type: 'boolean',
+                    description: 'For action=get with mode=error: include full stack trace (default: false, shows truncated)'
+                },
+                includeExecutionPath: {
+                    type: 'boolean',
+                    description: 'For action=get with mode=error: include execution path leading to error (default: true)'
+                },
+                fetchWorkflow: {
+                    type: 'boolean',
+                    description: 'For action=get with mode=error: fetch workflow for accurate upstream detection (default: true)'
+                },
                 limit: {
                     type: 'number',
                     description: 'For action=list: number of executions to return (1-100, default: 100)'