refactor: update keyboard shortcuts to prevent conflicts (#100)

Change Keyboard Shortcuts dialog shortcut from Cmd+H to Cmd+.
Update memory debug shortcut from Cmd+Shift+M to Cmd+Shift+D
Modify model selector shortcut to use Cmd+Shift+M

packages/desktop/src-tauri/src/main.rs

@@ -481,7 +481,7 @@ fn build_macos_menu<R: tauri::Runtime>(
         MENU_ITEM_TOGGLE_MEMORY_DEBUG_ID,
         "Toggle Memory Debug",
         true,
-        Some("Cmd+Shift+M"),
+        Some("Cmd+Shift+D"),
     )?;
 
     // Help menu items
@@ -490,7 +490,7 @@ fn build_macos_menu<R: tauri::Runtime>(
         MENU_ITEM_HELP_DIALOG_ID,
         "Keyboard Shortcuts",
         true,
-        Some("Cmd+H"),
+        Some("Cmd+."),
     )?;
 
     let download_logs = MenuItem::with_id(