fix: preserve composed iOS terminal input

[ZacharyZcR]

Summary

• let iOS terminal text input send the composed text from the active keyboard layout
• avoid sending printable iOS keypress values before Option-key composition completes
• keep virtual Ctrl/Alt/Shift handling and special-key handling unchanged
• fix local keyboard settings type/lint errors touched by validation

Fixes Termix-SSH/Support#311

Validation

• npx tsc --noEmit --pretty false
• npx eslint app/tabs/sessions/Sessions.tsx app/tabs/settings/KeyboardCustomization.tsx