fix(prompt): follow-ups from the omp approval-card review (#2106) #2124

Follow-up to #2106 (non-blocking findings from the merge pass's final review).

• Remember-ticked grants still get a generic card (Codex MEDIUM): the parser returns null, but server/prompt.ts ~614 substitutes a fallback card offering Up, Down, Enter and Esc (kind: "menu", fallback: true). Suppress the fallback for recognized panels deliberately left to the terminal.
• Details key collision (omo L1, server/dialogs/omp.ts ~270/391): 18.13 checks its details key before Deny and the arrows; a user binding Deny, Up/Down or select to the details key opens details instead and the card goes stale. Add the drawn details key to the collision check.
• Hidden second bindings (omo L2): omp's hint shows only the first key bound to deny, select and the arrows; a hidden second binding could turn a move into a Deny. Worth a comment.