Add context menu and refine project row UI
Add a reusable ContextMenu component and export. Integrate it into
the project table row, refactor the action buttons into a centered
flex layout and adjust button/loading/terminal visuals and behavior.
Update Navbar FAQs link to external docs and remove the Snapshots link
from the sidebar. Constrain the Projects table container height and make
the Sandbox page full-height with vertical overflow hidden.