v0.3.1 — clearer Skip/Defer, reduced-motion support

A small clarity and accessibility release.

Added

• Skip and Defer now explain themselves. Each carries an always-visible sub-label —
  Skip is "No opinion — don't ask again", Defer is "Matters — ask me next round" — so the
  two are told apart without hovering. Both also gain an aria-label combining the two.
• The Skip/Defer semantics, including the fact that Defer satisfies the required gate
  while Skip is offered only on optional questions, are now documented in SKILL.md.

Fixed

• prefers-reduced-motion: reduce now disables the card fade-in and progress-bar
  transition. This is an accessibility fix, and it also de-flaked headless screenshot
  capture, which could otherwise photograph a card mid-fade.