Expand command palette action coverage

[devmobasa]

Body:

Summary

• Add board/page lifecycle actions to the command palette: new/delete board, duplicate/delete/restore page
• Expose useful toolbarless utility commands such as marker opacity, font size, reset counters, selection properties, context menu, and refresh zoom
• Strengthen action metadata tests so command-palette coverage is checked as an exact contract

Notes

• Board/page delete confirmation remains handled by the existing delete action flow
• New board and duplicate page are exposed without confirmation because they are non-destructive