v0.4.3

State-threading patch — fixes a class of bug where the standalone
probe path silently dropped scan-level state on its way to probe
pages. Same family as the v0.4.2 getComputedStyle(target, ':focus-visible') fix: API used correctly at one layer, internal
plumbing failed to propagate to the next.

Specifically: --dark-mode set Playwright color_scheme="dark" only
on the initial HTML fetch, not on the 5 probe pages that ran after.
Each probe (contrast, tab_walk, dialog, carousel, form)
opened its own chromium context via standalone_page() and the call
sites in scanner.py did not pass color_scheme through. The
shared-browser path (_scan_page_with_browser, used by the site
command) was unaffected — it opens one context per URL and reuses
that page across all probes.

User impact: a11y-moda scan <url> --dark-mode returned only
light-mode probe results. --dark-mode was effectively a no-op for
the single-page command. The site command worked correctly.

Diagnosis credit: the bug was identified by independent analysis from
a teammate reviewing the v0.4.2 audit report against MODA's flagged
contrast finding (#c7cdd3 on #868789, ratio 2.24 — homepage
Integration component, dark-only).

Fixed

• tools/contrast.py collect_text_samples — now accepts
  color_scheme: str | None, threads to standalone_page().
• tools/tab_walk.py walk_tab_stops — same.
• tools/dialog_probe.py probe_dialogs — same.
• tools/carousel_probe.py probe_carousels — same.
• tools/form_probe.py probe_forms — same.
• scanner.py standalone path (lines 151-157) — passes
  color_scheme=color_scheme through to all 5 probe wrappers.

Verified

a11y-moda scan https://www.light-design.com.tw --render --dark-mode --level AAA after the fix correctly emits [深色模式] GN2140300E

• GN3140600E for the Integration component (「整合您現有的系統與 工具」 ratio=1.00, white-on-near-white) — the same element MODA's
  human auditor flagged. Pre-fix, both rules emitted nothing.

Notes

• Why site --dark-mode already worked — the shared-browser path
  uses page_session(browser, color_scheme=color_scheme) once per
  URL, and all probes operate on that one already-configured page.
  Standalone path was the regression because each probe opens its
  own context.
• Probe wrapper signatures unchanged for callers that don't need
  dark-mode — color_scheme defaults to None, behavior identical
  to pre-0.4.3 when omitted.
• Unrelated colleague findings (out of 0.4.3 scope) — APG tabs
  pattern (keyboard sim + roving tabindex) and carousel ←→ key
  pause-on-focus are feature gaps, not bugs. Tracking for 0.5.x.
  HM1240404E same-href context-difference detection requires LLM
  judgment; current logic correctly skips when href matches.
  GN1240500E caveat-vs-MODA-fail severity is a design choice.