fix: log error cause chain in logerror function

[OP-Prajwal]

Fixes #6462

Problem

The logerror function in Express was only logging err.stack, which doesn't display the error cause property introduced in Node.js 16.9.0. This meant that error chains were not visible in logs, making debugging more difficult.

Solution

Modified the logerror() function to explicitly log the complete error cause chain. When an error has a cause, it now logs each error in the chain with a "Caused by:" prefix for clarity.

Changes

• Updated lib/application.js - logerror() function now iterates through the error cause chain
• Maintains backward compatibility - errors without cause work exactly as before
• All existing tests pass (1236 passing)

Before

Error: Failed to fetch user data
    at ...

After

Error: Failed to fetch user data
    at ...

Caused by: Error: Failed to execute query
    at ...

Caused by: Error: Database connection timeout
    at ...

Testing

• All existing tests pass (1236 passing)
• Tested with error chains using Node.js Error.cause
• Backward compatible with errors without cause
• Requires Node.js 16.9.0+ for Error.cause support