fix: warn when favicon.ico is missing in generated project

[Samridhi-2007]

Related Issue

Fixes #415

Problem

When creating a new Neutralinojs application using:

neu create
cd
neu run

the application logs a runtime error:
Unable to load application resource file /resources/favicon.ico

Root Cause

The default template (neutralinojs/neutralinojs-minimal) does not include a favicon.ico file in the resources/ directory. This results in runtime error logs, which can be confusing for new users.

Solution

This PR introduces a proactive check during project creation:

• Detects if resources/favicon.ico is missing
• Displays a clear warning message to the user instead of relying on runtime errors

Changes Made

• Added a file existence check for resources/favicon.ico in:
  src/modules/creator.js

• Displays the following warning if the file is missing:

Warning: favicon.ico not found in resources/. This file is optional but recommended.

Impact

• Improves developer experience
• Reduces confusion caused by runtime error logs
• Provides clearer feedback to users without affecting existing functionality

Testing

• Created a new project using neu create
• Verified that the warning message appears correctly
• Confirmed that existing functionality remains unchanged

Note

A potential future improvement would be to include a default favicon.ico in the template repository to eliminate this issue entirely.