A11y: colour-contrast sweep — the gate's allowlist is now empty

[adamXbot]

Summary

Fixes every colour-contrast suppression the a11y gate carried, driven by axe's own measured colour pairs (probed on all five scanned surfaces rather than guessed):

• Light-theme --blue: #0071e3 → #0066cc — clears the active detail tab and footer links as text on tinted surfaces (4.2 → 5.0) and raises white-on-blue button labels (coachmark Next, task-journey CTA) to 5.6.
• Floating pills (SiteInfoHint, kbd-hint): resting opacity 0.75 → 1 — the container opacity diluted the already-muted --text-2 links to ~3.1:1; the translucent color-mix background + blur keep the quiet look without the failure.
• task-list.css: six var(--text-secondary, rgba(…, 0.85)) → var(--text-2, #6c6c80) — --text-secondary is not a defined token anywhere, so the ~3.0:1 translucent fallback always fired. (Two were axe-flagged; the other four are the same defect in states the scans happened not to render — the source of the gate's TaskList state-flakiness.)
• .home-layout-footer-secondary: drop the 0.85 opacity (3.9 → 5.4). .home-section-count: full --text on its tinted pill.
• .detail-a11y-chip: theme-aware foreground (color-mix of --blue toward --text — darker in light mode, lighter in dark; 2.65 → ~4.9 on the grey hero surface), resting tint 18% → 12%, count pill on --text.
• .nav-drawer-link + .count-badge: full-strength --text — the drawer is a translucent liquid-glass surface over arbitrary content, where muted text cannot guarantee 4.5:1 on every blend.

Gate changes

All contrast(…) allowlist entries, the helper, and the reason string are deleted — the a11y gate now runs with a completely empty allowlist. The dashboard and mobile-nav scans gain a 600ms settle so axe stops measuring the coachmark/drawer entrance animations mid-fade — the two previously state-dependent flags turn out to have been exactly that.

Verification

• Standalone axe probe: zero contrast violations across all five surfaces post-fix.
• a11y spec run twice back-to-back: identical, all green.
• Full Playwright suite: 34 passed; 441 unit tests; typecheck + lint clean.
• Dark theme: the changed selectors either use theme-aware tokens (--blue, --text) or improve in both themes; dark mode remains unmeasured by the gate (it scans the default colour scheme).

🤖 Generated with Claude Code

[adamXbot]

Cherry-picked the postcss advisory fix onto this branch so it goes green independently of merge order — see #141 for the full diagnosis.

Short version: a new PostCSS advisory (GHSA-r28c-9q8g-f849, fixed in 8.5.18) turned the quality job red on every open PR and on main's Docker publish, with nobody having changed code. The existing ^8.5.12 override wasn't enough — a caret is not a floor that moves, and the lockfile had resolved the vulnerable 8.5.17.

If #141 merges first, this commit drops out cleanly on rebase (identical patch).

🤖 Generated with Claude Code