Revoking an invite link in the terminal asks first: `x` names the link, `y` revokes, `n` or esc keeps it open #7960

Intent: a revoked invite cannot be reopened (the person holding it is shut out until a new one is minted), so the terminal asks before it does it, as its own s already asks before signup changes.

Today src/tui/screens/invites.ts revokes the selected open link the moment x is pressed.

Done looks like:

• [ ] x on an open link opens confirmScreen (from src/tui/screens/common.ts, yesNo: true) titled "Revoke invite <id>?" with one body line saying when it expires and that whoever holds it can no longer sign up with it.
• [ ] y (or the Revoke button) revokes through the action and the line reads "Revoked <id>." as today; n or esc revokes nothing and the link is still open.
• [ ] x on a link that is not open says INVITE_NOT_OPEN as today, without a confirm.
• [ ] test/tui-invites.test.ts: the existing revoke test presses y after x; a new test presses x then n and proves the link is still open. The new test fails without the change.
• [ ] bun test test/tui-invites.test.ts passes.

Files: src/tui/screens/invites.ts, test/tui-invites.test.ts Risks: the minted link is shown once until the next key; the confirm must not bring it back. Brief: a builder who knows the terminal screens.