Make permission prompt numbering configurable

Feature Request

Problem

The permission prompt options use inconsistent numbering across different contexts:

• Sometimes it's 1 = Yes, 2 = No
• Other times it's 1, 2, 3 = Yes (with variations), 4 = No

This inconsistency makes it easy to accidentally approve or deny actions. There's no way to configure which number maps to which response.

Proposed Solution

Make the permission prompt key mappings configurable, e.g. in ~/.claude/settings.json:

{
  "permissionPrompt": {
    "denyKey": "9"
  }
}

This would allow users to set a consistent "deny" key (e.g., always 9 for No) regardless of how many approval options are presented. This prevents accidental approvals when the number of options changes between prompts.

Why This Matters

• Muscle memory: Users develop habits around key presses. Inconsistent deny keys lead to mistakes.
• Safety: Accidentally approving a destructive operation because the "No" key moved is a real risk.
• Accessibility: Users should be able to configure their own key mappings for critical safety prompts.

Suggested Implementation

• Allow configuring denyKey in settings (default remains current behavior)
• The deny key should be consistent across all permission prompts regardless of how many options exist
• Could also allow configuring approveKey, approveForSessionKey, etc.