v0.4.1

Patch fixing two real-audit gaps that v0.4.0 dogfood scan revealed:

1. CS2240700E (skip-link target focus) was emitting nothing on
   light-design.com.tw even though the MODA AAA report flagged
   exactly this pattern. Root cause: the dialog_probe correctly
   pressed Enter on the skip link, but browsers do not move keyboard
   focus on <a href="#x"> activation unless the target carries
   tabindex="-1". The probe's opened flag stayed False. The rule
   only fired when opened=True AND visible_focus=False, so the
   "Enter pressed but focus didn't move" case (the most common
   violation) was silently passed.

2. --dark-mode was a one-or-the-other switch — it scanned ONLY in
   dark mode, replacing the default light scan instead of adding to
   it. Most contrast bugs only appear in one variant; the other has
   to be re-scanned manually. Now --dark-mode runs both passes and
   merges, with dark-only issues prefixed [深色模式] so the merged
   report makes attribution obvious.

Coverage delta on the 9-finding MODA AAA audit (light-design.com.tw,
2026-05-12 dogfood): 5/9 stable HITs in v0.4.0 → 5/9 stable HITs in
v0.4.1, but the quality improved — CS2240700E is now a true
match and GN2140300E aligns to the MODA-flagged dark-mode contrast
segment instead of an unrelated light-mode segment. GN1220200E
(carousel pause) remains intermittent due to Wix Reviews lazy-mount
timing — pre-existing flake, not regressed by this release.

Added

• DialogProbeResult.skip_link_found — distinguishes "probe
  found a skip link and pressed Enter" from "probe found nothing".
  Required so CS2240700E can fire on the "Enter pressed but focus
  didn't move" case without false-firing on pages that simply lack a
  skip link (the latter is GN1240100E's domain).
• scanner.merge_dark_into_report + _merge_dark_into_page —
  combines a dark-mode ScanReport / PageReport into the
  corresponding light report. Dark-only issues (after exact
  (rule_id, snippet, message) dedup) get the [深色模式] prefix.

Changed

• CS2240700E — now emits two distinct fail messages:
  • Enter 後焦點未跳至目標元素 when the skip link was activated but
    document.activeElement did not become the target (most common
    violation — target lacks tabindex="-1").
  • 焦點已跳至目標但目標元素無可見焦點指示 when focus did move but
    the target's :focus-visible style is empty (existing case,
    refined wording).
• --dark-mode flag semantics — was "scan only in dark"; is now
  "scan in light AND dark, merge results". Behavioral change for
  anyone scripting against the flag, but more useful in practice
  (dual coverage in one command). Help text updated.

Notes

• Flake disclosure — GN1220200E (carousel pause) detection
  depends on Wix Reviews lazy-mounting before the 4.5s observation
  window expires. On light-design.com.tw this hits ~50% of runs.
  Not regressed by 0.4.1; will be addressed in a follow-up via
  pre-probe scroll + extended observation when no motion is detected
  in the first window.
• Why 0.4.1 not 0.4.0.1 — --dark-mode semantic change is a
  user-visible behavior shift. SemVer-strict would call this minor,
  but pre-1.0 we keep it as patch since the flag was new in 0.4.0
  and the new behavior is what users actually wanted.
• No README rewrite needed — --dark-mode description in README
  already said "Run twice (light + dark) for full coverage" — the
  CLI now matches what the README promised.