fix: preserve complete session loading error details

packages/node-runtime/src/ai/agent/__tests__/core.test.ts

@@ -243,8 +243,9 @@ describe('runAgentCore runtime contract', () => {
       })
     )
     assert.equal(result.error, undefined)
-    assert.equal(captured?.messages[0].content[0].type, 'text')
-    assert.equal(captured?.messages[0].content[0].text, historyText)
+    const firstBlock = captured?.messages[0].content[0]
+    assert.ok(typeof firstBlock === 'object' && firstBlock.type === 'text')
+    assert.equal(firstBlock.text, historyText)
     assert.equal(outputBudget, 2048, 'Preserve the configured output budget when the history and answer both fit')
   })
 

packages/node-runtime/src/logging/app-logger.ts

@@ -10,7 +10,7 @@
 
 import * as fs from 'fs'
 import * as path from 'path'
-import { extractErrorInfo, extractErrorStack } from '../ai/ai-logger'
+import { extractErrorInfo } from '../ai/ai-logger'
 
 type LogLevel = 'DEBUG' | 'INFO' | 'WARN' | 'ERROR'
 
@@ -92,7 +92,7 @@ function formatData(data: unknown): string {
   if (data === undefined) return ''
   if (data instanceof Error) {
     const info = extractErrorInfo(data)
-    const stack = extractErrorStack(data)
+    const stack = data.stack
     return JSON.stringify(info) + (stack ? `\n${stack}` : '')
   }
   if (typeof data === 'string') return data