Enhance test for broken themes scenario

Added comprehensive test covering the exact scenario from the issue including attempting to install a broken theme

Co-authored-by: swissspidy <[email protected]>

Author: Copilot

features/theme.feature

@@ -440,12 +440,35 @@ Feature: Manage WordPress themes
     Given a WP install
     And I run `wp theme install moina`
     And I run `wp theme install moina-blog`
-    And I run `wp theme delete moina`
-
+    
+    When I run `wp theme list --fields=name,status`
+    Then STDOUT should be a table containing rows:
+      | name          | status   |
+      | moina-blog    | inactive |
+      | moina         | inactive |
+    
+    When I run `wp theme delete moina`
+    Then STDOUT should contain:
+      """
+      Deleted 'moina' theme.
+      """
+    
     When I run `wp theme list --fields=name,status`
     Then STDOUT should be a table containing rows:
       | name          | status   |
       | moina-blog    | inactive |
+    
+    When I try `wp theme activate moina-blog`
+    Then STDERR should contain:
+      """
+      Error: The parent theme is missing. Please install the "moina" parent theme.
+      """
+    
+    When I try `wp theme install moina-blog`
+    Then STDERR should contain:
+      """
+      Warning: moina-blog: Theme already installed.
+      """
 
   Scenario: When updating a theme --format should be the same when using --dry-run
     Given a WP install