Implement d6 wild dice/fumble skills and die-state rolls

UX.md

@@ -250,6 +250,9 @@ Actions:
 
 - `Create Skill` button -> modal form
 - `Edit Skill` button -> modal form
+- d6 skill forms include:
+  - `Wild dice` numeric field
+  - `Allow fumble` toggle
 - Roll command panel:
   - Visibility selector (`public`, `private`)
   - `Roll Skill` primary action
@@ -258,6 +261,7 @@ Last roll card:
 
 - Result total
 - Breakdown
+- Die-by-die visualization with states: `critical`, `fumble`, `wild`, `removed`, `added`
 - Visibility
 - Timestamp