feat: add <kindred> element to package.xml

Declares min_create_version=0.1.0, load_priority=60, pure_python=true,
and documents universal overlay context.

freecad/package.xml

@@ -12,4 +12,14 @@
             <subdirectory>./</subdirectory>
         </workbench>
     </content>
+
+    <!-- Kindred Create extensions -->
+    <kindred>
+        <min_create_version>0.1.0</min_create_version>
+        <load_priority>60</load_priority>
+        <pure_python>true</pure_python>
+        <contexts>
+            <context id="*" action="overlay"/>
+        </contexts>
+    </kindred>
 </package>