Add interactive arrow-key Yes/No prompt

[bguidolim]

Summary

Upgrades askYesNo from plain text input (type y or n) to an interactive horizontal arrow-key selector, consistent with the existing singleSelect and multiSelect UX. Also refactors shared raw terminal infrastructure to eliminate duplication across all three interactive prompts, and standardizes hint line placement and style.

Changes

• Add interactiveYesNo with horizontal › Yes No layout using left/right arrows, y/n shortcuts, Enter/Space to confirm
• Extract withRawTerminal(_:) helper replacing 3 duplicated raw terminal setup/teardown blocks
• Extract readCSIArrowKey() helper replacing 3 duplicated CSI escape sequence parsers
• Add stored isInteractiveTerminal property replacing 3 identical TTY checks
• Move multi-select keyboard hint from top (inline prose) to bottom (dim with · separators), matching single-select and yes/no style
• Non-TTY fallback preserves existing [Y/n] text input behavior — all 10 call sites unchanged

Test plan

• swift test passes locally (866 tests)
• swiftformat --lint . and swiftlint pass without violations
• Affected commands verified with a real pack (e.g. mcs sync, mcs cleanup, mcs pack remove, mcs doctor --fix)