Migrate jQuery to Alpine and JavaScript

[nerometa]

Nullboard currently relies on jQuery for DOM manipulation and UI logic. To modernize the codebase, improve maintainability, and reduce dependencies, I'll be migrating all jQuery-based functionality to Alpine.js and vanilla JavaScript where applicable.

Tasks:

• Identify all usages of jQuery throughout the codebase
• Replace jQuery DOM manipulation and event handling with Alpine.js directives and JavaScript
• Remove jQuery from dependencies and build process
• Test all affected features for regressions
• Update documentation to reflect the migration

Benefits:

• Smaller bundle size
• Improved maintainability
• Modern, declarative UI logic.