🧪 Fix langSysTag test expectations for padded tags

Commit 6c28834 added space-padding to `langSysTag` values to work
around pdf-core expecting 4-character tags, but the tests were not
updated to match.

Update 4 test expectations in `text.test.ts` to expect `'DEU '`
instead of `'DEU'`.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ralfstx

src/text.test.ts

@@ -198,7 +198,7 @@ describe('text', () => {
 
       expect(shapeTextSpy).toHaveBeenCalledWith('foo', {
         scriptTag: 'latn',
-        langSysTag: 'DEU',
+        langSysTag: 'DEU ',
       });
     });
 
@@ -301,19 +301,19 @@ describe('text', () => {
     });
 
     it('includes langSysTag when language is set', () => {
-      expect(buildShapeOptions({ language: 'de' })).toEqual({ langSysTag: 'DEU' });
+      expect(buildShapeOptions({ language: 'de' })).toEqual({ langSysTag: 'DEU ' });
     });
 
     it('combines langSysTag with scriptTag', () => {
       expect(buildShapeOptions({ language: 'de' }, 'latn')).toEqual({
         scriptTag: 'latn',
-        langSysTag: 'DEU',
+        langSysTag: 'DEU ',
       });
     });
 
     it('combines langSysTag with features', () => {
       expect(buildShapeOptions({ language: 'de', fontKerning: 'none' })).toEqual({
-        langSysTag: 'DEU',
+        langSysTag: 'DEU ',
         features: { kern: false },
       });
     });