fix(wix): split ProgID per extension to avoid duplicate Verb registry key

A single ProgID with two `<Extension>` children, each carrying its own
`<Verb Id='open'>`, makes WiX emit two rows with the same Registry
primary key and light fails with LGHT0130. Split into one ProgID per
extension (`OpenCADStudio.DWG`, `OpenCADStudio.DXF`); both still invoke
the same exe with the file as `argv[1]`.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

packaging/windows/main.wxs

@@ -72,18 +72,26 @@
             </File>
 
             <!--
-              File association: a single ProgID handles both .dwg and
+              File associations. Two ProgIDs (one per extension) so the
-              .dxf. ContentType isn't strictly required on Windows but
+              `<Verb Id='open'>` rows don't collide on the same registry
-              improves "Open with…" suggestions.
+              primary key — both ProgIDs invoke the same exe with the
+              file path as `argv[1]`.
             -->
             <ProgId
-              Id='OpenCADStudio.Drawing'
+              Id='OpenCADStudio.DWG'
-              Description='Drawing'
+              Description='DWG Drawing'
               Icon='OpenCADStudioEXE'
               IconIndex='0'>
               <Extension Id='dwg' ContentType='image/vnd.dwg'>
                 <Verb Id='open' Command='Open' TargetFile='OpenCADStudioEXE' Argument='"%1"' />
               </Extension>
+            </ProgId>
+
+            <ProgId
+              Id='OpenCADStudio.DXF'
+              Description='DXF Drawing'
+              Icon='OpenCADStudioEXE'
+              IconIndex='0'>
               <Extension Id='dxf' ContentType='image/vnd.dxf'>
                 <Verb Id='open' Command='Open' TargetFile='OpenCADStudioEXE' Argument='"%1"' />
               </Extension>