Improve error handling and optimize character lookup

[codewithdhruba01]

• Updated error handling to prevent exposing internal error details to the client.
• Now logs only error messages on the server for debugging purposes.
• Sends a user-friendly error message ("An unexpected error occurred. Please try again later.") when an error happens.
• Optimized the getCharacterByName function by replacing the loop with Array.prototype.find() for cleaner and more efficient character lookup.
• Minor code formatting improvements for better readability.

📋 Checklist:

• Tested the server locally
• Verified correct error messages returned
• Code runs without breaking existing functionality

[softchris]

@codewithdhruba01 thanks for the effort :)