feat(10.2-01): add error and trace logging utility nodes

- Create Log Error code node with ring buffer write logic
- Create Log Trace code node with debug mode check and auto-disable
- Both nodes implement ring buffer (max 50 entries) with auto-rotation
- Log Error: accepts error data, truncates large fields (stack 500, raw 1000)
- Log Error: passes through input data with _errorLogged flag
- Log Trace: checks debug.enabled before logging, passes through unchanged
- Log Trace: auto-disables debug mode after 100 executions
- Both nodes positioned at utility area (2600, -200/-400)
- Nodes are standalone (no connections) - ready for Plan 02 wiring
- Node count: 170 -> 172 (+2 utility nodes)

n8n-workflow.json

@@ -4941,6 +4941,32 @@
           "name": "Telegram account"
         }
       }
+    },
+    {
+      "parameters": {
+        "jsCode": "const staticData = $getWorkflowStaticData('global');\nconst input = $input.item.json;\n\n// Initialize if needed\nif (!staticData.errorLog) {\n  staticData.errorLog = {\n    debug: { enabled: false, executionCount: 0 },\n    errors: { buffer: [], nextId: 1, count: 0, lastCleared: new Date().toISOString() },\n    traces: { buffer: [], nextId: 1 }\n  };\n}\n\nconst MAX_ERRORS = 50;\nconst errorEntry = {\n  id: `err_${String(staticData.errorLog.errors.nextId).padStart(3, '0')}`,\n  correlationId: input.correlationId || $execution.id,\n  timestamp: new Date().toISOString(),\n  executionId: $execution.id,\n  workflow: input.workflow || 'main',\n  node: input.node || 'unknown',\n  operation: input.operation || 'unknown',\n  userMessage: input.userMessage || input.errorMessage || 'Unknown error',\n  error: {\n    message: input.errorMessage || 'Unknown error',\n    stack: (input.errorStack || '').substring(0, 500),\n    httpCode: input.httpCode || null,\n    rawResponse: (input.rawResponse || '').substring(0, 1000)\n  },\n  context: input.contextData || {}\n};\n\n// Ring buffer: push and rotate\nstaticData.errorLog.errors.buffer.push(errorEntry);\nif (staticData.errorLog.errors.buffer.length > MAX_ERRORS) {\n  staticData.errorLog.errors.buffer.shift();\n}\nstaticData.errorLog.errors.nextId++;\nstaticData.errorLog.errors.count++;\n\n// Pass through all input data so downstream nodes still work\nreturn { json: { ...input, _errorLogged: true, _errorId: errorEntry.id } };"
+      },
+      "id": "code-log-error",
+      "name": "Log Error",
+      "type": "n8n-nodes-base.code",
+      "typeVersion": 2,
+      "position": [
+        2600,
+        -200
+      ]
+    },
+    {
+      "parameters": {
+        "jsCode": "const staticData = $getWorkflowStaticData('global');\nconst input = $input.item.json;\n\n// Initialize if needed\nif (!staticData.errorLog) {\n  staticData.errorLog = {\n    debug: { enabled: false, executionCount: 0 },\n    errors: { buffer: [], nextId: 1, count: 0, lastCleared: new Date().toISOString() },\n    traces: { buffer: [], nextId: 1 }\n  };\n}\n\n// Check if debug mode is enabled\nif (!staticData.errorLog.debug.enabled) {\n  // Debug mode off, pass through unchanged\n  return { json: input };\n}\n\n// Increment execution count and check auto-disable threshold\nstaticData.errorLog.debug.executionCount++;\nif (staticData.errorLog.debug.executionCount >= 100) {\n  staticData.errorLog.debug.enabled = false;\n  // Note: Auto-disable happened, but we don't have a way to notify here\n  // The /debug status command will show it's disabled\n}\n\nconst MAX_TRACES = 50;\nconst traceEntry = {\n  id: `trace_${String(staticData.errorLog.traces.nextId).padStart(3, '0')}`,\n  correlationId: input.correlationId || $execution.id,\n  timestamp: new Date().toISOString(),\n  executionId: $execution.id,\n  event: input.event || 'unknown',  // \"sub-workflow-call\" | \"callback-routing\"\n  workflow: input.workflow || 'main',\n  node: input.node || 'unknown',\n  data: input.traceData || {}\n};\n\n// Ring buffer: push and rotate\nstaticData.errorLog.traces.buffer.push(traceEntry);\nif (staticData.errorLog.traces.buffer.length > MAX_TRACES) {\n  staticData.errorLog.traces.buffer.shift();\n}\nstaticData.errorLog.traces.nextId++;\n\n// Pass through all input data unchanged\nreturn { json: { ...input, _traceLogged: true, _traceId: traceEntry.id } };"
+      },
+      "id": "code-log-trace",
+      "name": "Log Trace",
+      "type": "n8n-nodes-base.code",
+      "typeVersion": 2,
+      "position": [
+        2600,
+        -400
+      ]
     }
   ],
   "connections": {