WIP: Sheet Set Manager palette, wizard, properties and sheet set fields

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/modules/view/sheetset.rs

@@ -5,6 +5,6 @@ pub fn tool() -> ToolDef {
         id: "SHEETSET",
         label: "Sheet Set\nManager",
         icon: ICON,
-        event: ModuleEvent::Command("SHEETSET".to_string()),
+        event: ModuleEvent::Command("_SSMTOGGLE".to_string()),
     }
 }