Implement key repeat for virtual keyboard

[mrinaldi]

Overview

This PR adds long-press key repeat to the Termix Mobile virtual keyboard. Hold down arrow keys, backspace, delete, space, or Page Up/Down for fast input—like you'd expect on a real keyboard.

• Added: Key repeat on long-press for navigation and editing keys
• Added: Repeat settings in keyboard customization UI
• Updated: Keyboard keys to handle long-press repeat
• Updated: Input fields now have better tap targets for easier focus

Changes Made

Key Repeat Feature

• Created a new keyboard-repeat-config.ts constant file and useKeyRepeat hook (React hooks with proper cleanup via refs)
• Supports repeating: arrow keys, backspace, delete, space, Page Up, Page Down
• Character keys are excluded so they still show the emoji/country flag menus
• Default settings: 250ms before repeat starts, 100ms between repeats (slightly longer than desktop to feel natural on touch screens)
• Added input fields to the keyboard settings UI so users can tune the behavior (delay + speed)

Small UX Improvement

• Moved padding onto the TextInput itself in Input.tsx instead of wrapping it in a View. Makes focus input fields easier.

Related Issues

No specific issue.

Screenshots / Demos

(Feature is hard to screenshot—just try holding down any arrow key or backspace in a terminal to see it.)

Screenshot of the new settings is below

Checklist

• Code follows project style guidelines
• Supports mobile (React Native for iOS + Android)
• I have read Contributing.md