Add schedule preview dropdown styles and various improvements

- Add .schedule-preview-dropdown and .schedule-preview-item CSS classes
- Add .btn-schedule-preview badge styling
- Add preview functionality for entity list views
- Improve modal and dropdown styling
- Various JS and SCSS enhancements

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

gulpfile.js

@@ -39,9 +39,9 @@ const paths = {
 function scssTask() {
     return gulp.src(paths.scss.src)
         .pipe(sourcemaps.init())
-        .pipe(sass({
-            outputStyle: 'compressed',
-            charset: false  // Prevent UTF-8 BOM in output
+        .pipe(sass.sync({
+            style: 'compressed',
+            silenceDeprecations: ['legacy-js-api']
         }).on('error', sass.logError))
         .pipe(rename('entity-selector.css'))
         .pipe(sourcemaps.write('.'))