Kntnt Popup 1.1.1

improve: reorganize build system with better project structure

* Move build.js to scripts/build.js for better organization
* Create scripts/dev-build.js for development setup workflow
* Update package.json scripts to reference new file locations
* Move micromodal from js/ to vendor/micromodal/ directory
* Update assets.php to load micromodal from vendor location
* Switch from zip-a-folder to archiver for more stable ZIP creation
* Move micromodal from dependencies to devDependencies in package.json
* Update build process to include vendor directory in distribution
* Improve error handling and logging in build scripts

Follows WordPress best practices and improves developer experience
without changing end-user functionality.