fix: preserve full error details in logerror (Error.cause, nested errors)

[armorbreak001]

Problem

logerror() currently logs err.stack || err.toString(). This strips important error information:

• Error.cause (ES2022) — nested/wrapped errors are invisible in logs
• Custom properties — libraries like Sequelize attach parent, original, and other diagnostic properties that get lost
• Async context — modern Node.js includes richer info when logging the full Error object

Real-world impact

When using Sequelize (or any library that wraps errors), Express currently logs just Error: with an unhelpful stack trace. The actual database error details (constraint violation, connection failure reason, etc.) are hidden inside properties that err.stack does not include.

Solution

One-line change: console.error(err.stack || err.toString()) → console.error(err)

This preserves the complete error object output while still showing stack traces. Node's console.error handles Error objects comprehensively — it prints the message, cause chain, custom properties, and stack.

Before

Error: 
    at Object.<anonymous> (/app/index.js:25:3)
    ...

(No indication of what actually went wrong)

After

Error: inner error message
    at Object.<anonymous> (/app/index.js:23:3)
    ...
[cause]: Error: outer wrapper

Testing

• All 1249 existing tests pass
• Behavior verified: console.error(new Error("outer", { cause: new Error("inner") })) now shows both errors
• Non-Error values still work (coerced to string by console.error)

Backwards Compatibility

Fully backwards compatible. The output is strictly more informative — no information is removed, only added.

Fixes #6462

[krzysdz]

Duplicate of #6464