v25.0.6: Fix bootstrap-datepicker and select2 integration for Bootstrap 5

Major improvements and fixes:

## Bootstrap-datepicker Integration
- Fix DPGlobal undefined error in date input
- Remove conflicting bdatepicker alias that was causing noConflict errors
- Add graceful error handling for missing bootstrap-datepicker dependency
- Implement proper initialization sequence for DPGlobal API
- Position datepicker above input with improved UX styling

## Select2 Integration & Compatibility
- Fix select2 integration with Select2 v4.1.0-rc.0
- Resolve issue where select2:select event fired but value didn't update
- Add event handler to manually update select2 value on selection
- Fix webpack build inconsistency between demo and standalone builds
- Remove redundant npm dependencies from demo (bootstrap-datepicker, select2)
- Implement proper Select2 v4 API usage for value setting

## Build System Improvements
- Fix webpack configuration to properly handle CSS imports
- Remove CSS file copying for npm dependencies, use webpack imports instead
- Ensure consistent input type registration across all build targets
- Clean up build output and remove debugging code

## Demo & Testing
- Update demo to use webpack source build for consistency
- Add comprehensive error handling and user feedback
- Clean up all debugging console output
- Improve demo page descriptions and usability

## Technical Fixes
- Fix 'Unknown type: select2' error in demo build
- Resolve value change detection preventing save operations
- Implement savenochange option for better UX
- Remove deprecated jQuery UI conflicts and aliases
- Update to modern webpack and build practices

src/inputs/date/date.js

@@ -26,11 +26,7 @@ $(function(){
 (function ($) {
     "use strict";
     
-    //store bootstrap-datepicker as bdateicker to exclude conflict with jQuery UI one
-    $.fn.bdatepicker = $.fn.datepicker.noConflict();
-    if(!$.fn.datepicker) { //if there were no other datepickers, keep also original name
-        $.fn.datepicker = $.fn.bdatepicker;    
-    }    
+    
     
     var Date = function (options) {
         console.log('Date input constructor called');
@@ -70,7 +66,14 @@ $(function(){
             //language
             this.options.datepicker.language = this.options.datepicker.language || 'en'; 
 
-            //store DPglobal - use datepicker instead of bdatepicker
+            //store DPglobal - ensure bootstrap-datepicker is available
+            if (!$.fn.datepicker || !$.fn.datepicker.DPGlobal) {
+                console.error('Bootstrap-datepicker not found or DPGlobal not available');
+                console.error('Please include bootstrap-datepicker.js and bootstrap-datepicker.css in your page');
+                // Set error state instead of throwing
+                this.error = 'Bootstrap-datepicker is required but not found. Please include bootstrap-datepicker.js and bootstrap-datepicker.css';
+                return;
+            }
             this.dpg = $.fn.datepicker.DPGlobal; 
 
             //store parsed formats