fix: widget-demo scripts self-contained and mx-check clean

- Add CREATE MODULE and CREATE MODULE ROLE to 01-domain-model.mdl
- Add Attributes to DROPDOWNFILTER dfCat (was missing required binding)
- Replace LanguageSelector with placeholder (requires runtime config)
- Add ALTER USER ROLE to assign WidgetDemo.User to Administrator/User
- Fix dropdownfilter.def.json: attrChoice "linked" → "custom" for MDL

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: engalar

mdl-examples/widgetdemo/01-domain-model.mdl

@@ -1,6 +1,9 @@
 -- WidgetDemo: self-contained domain model (no external dependencies)
 -- Provides entities and enumerations for the widget showcase page.
 
+CREATE MODULE WidgetDemo;
+CREATE MODULE ROLE WidgetDemo.User;
+
 CREATE ENUMERATION WidgetDemo.ENUM_Priority (
   LOW 'Low',
   MEDIUM 'Medium',

mdl-examples/widgetdemo/03-showcase-page.mdl

@@ -104,7 +104,7 @@ CREATE OR REPLACE PAGE WidgetDemo.WidgetDemo_Showcase (
         ) {
           FILTER flt1 {
             TEXTFILTER tfTitle (Attributes: [Title, Code])
-            DROPDOWNFILTER dfCat
+            DROPDOWNFILTER dfCat (Attributes: [Category])
             NUMBERFILTER nfAmt (Attributes: [Amount])
             DATEFILTER dtfDate (Attributes: [DateCreated])
             PLUGGABLEWIDGET 'com.mendix.widget.web.dropdownsort.DropdownSort' ddSort1
@@ -425,7 +425,9 @@ CREATE OR REPLACE PAGE WidgetDemo.WidgetDemo_Showcase (
     -- 8f: Language + Accessibility
     ROW rowS8f {
       COLUMN cS8f1 (DesktopWidth: 6) {
-        PLUGGABLEWIDGET 'com.mendix.widget.web.languageselector.LanguageSelector' langSel1
+        -- LanguageSelector requires runtime data source and caption — omitted (needs running app)
+        -- PLUGGABLEWIDGET 'com.mendix.widget.web.languageselector.LanguageSelector' langSel1
+        DYNAMICTEXT langPlaceholder (Content: '[LanguageSelector — requires runtime config]', RenderMode: Paragraph)
       }
       COLUMN cS8f2 (DesktopWidth: 6) {
         PLUGGABLEWIDGET 'com.mendix.widget.web.accessibilityhelper.AccessibilityHelper' accHelper1 (targetSelector: '.mx-name-accHelper1') {

mdl-examples/widgetdemo/04-seed-and-navigate.mdl

@@ -96,3 +96,6 @@ END;
 /
 
 GRANT EXECUTE ON MICROFLOW WidgetDemo.SeedAndShowShowcase TO WidgetDemo.User;
+
+ALTER USER ROLE Administrator ADD MODULE ROLES (WidgetDemo.User);
+ALTER USER ROLE User ADD MODULE ROLES (WidgetDemo.User);

sdk/widgets/definitions/dropdownfilter.def.json

@@ -4,7 +4,7 @@
   "templateFile": "datagrid-dropdown-filter.json",
   "defaultEditable": "Always",
   "propertyMappings": [
-    {"propertyKey": "attrChoice", "value": "linked", "operation": "primitive"},
+    {"propertyKey": "attrChoice", "value": "custom", "operation": "primitive"},
     {"propertyKey": "attributes", "source": "Attributes", "operation": "attributeObjects"},
     {"propertyKey": "defaultFilter", "source": "FilterType", "operation": "primitive"}
   ]