feat(studio): add Record list right-click context menus

[SaadNiaziDev]

Summary

Closes #199.

Adds a reusable Studio ContextMenu design primitive (Reka, design layer only) and dogfoods it on Record list rows with Open, Copy Record name, and Copy link.

Design system

• New ContextMenu primitive sharing dropdown menu tokens (d-dropdown-menu__*)
• Exported from @dygo/ui / design index; covered by design-system export test

DataTable

• Optional contextMenuItems resolver per row
• context-menu-select event with { key, row, rowKey }
• Rows wrapped in ContextMenu only when a resolver is provided (left-click activate + selection unchanged)

Record list

• Right-click menu: Open, Copy Record name, Copy link (absolute URL)
• Success toasts on copy; actions disabled when the row has no name

Docs

• docs/studio.md — Context menus section; Entity actions remain on action bars for now

Out of scope (follow-up)

• Context menus on forms, sidebar, Activity, custom Pages
• Entity actions / Delete in the menu
• Command palette item sharing

Test plan

• Right-click a Record row → Studio menu at cursor (not browser-only)
• Open navigates like row activate
• Copy name / Copy link work and show toast
• Checkbox selection and left-click row open still work
• npm test --prefix apps/studio/ui

Made with Cursor