* test(a11y): add three-tier accessibility audit tooling Add Playwright + axe-core e2e tests for all 8 page types, pa11y-ci with WCAG2AA standard, and Lighthouse CI with accessibility score >= 95 assertion. Replace basic axe-core/cli CI job with proper three-tool pipeline including artifact uploads. Add manual VoiceOver and keyboard walkthrough checklists for human review. * fix(ci): build in accessibility job and fix standalone path Next.js standalone output mirrors the absolute filesystem path. Build within the accessibility job instead of downloading artifacts to ensure paths match. Start server before Playwright tests with reuseExistingServer. * fix(ci): use flat standalone paths for CI compatibility Next.js standalone output mirrors absolute filesystem paths locally but uses flat paths on CI runners. Use simple flat paths in CI workflow and dynamic path discovery in Playwright config for cross-platform support. * fix(a11y): increase destructive color contrast for dark mode Override --color-destructive in dark mode with #ff6369 (red-dark-11) for sufficient contrast against dark backgrounds. The previous #ce2c31 only achieved 3.53:1 ratio, below the WCAG AA minimum of 4.5:1. * fix(a11y): use Radix var refs for destructive colors Replace hardcoded destructive color values with var(--red-11), var(--red-12), and var(--red-1) references so Radix dark mode automatically provides AA-compliant contrast in both color schemes. Light: #ce2c31 text (5.21:1 vs white bg) Dark: #ff9592 text (8.95:1 vs dark bg) * fix(ci): install Chrome for pa11y-ci and Lighthouse pa11y-ci uses Puppeteer which needs its own Chrome binary. Install it explicitly via npx puppeteer browsers install. Set CHROME_PATH for Lighthouse CI to use system Chrome. * fix(ci): use pnpm exec for puppeteer browser install * fix(ci): use system Chrome for pa11y-ci in CI Convert .pa11yci.json to .pa11yci.js to conditionally set executablePath to system Chrome in CI environment. Removes the separate Chrome installation step. * fix(ci): remove dynamic routes from Lighthouse CI config Dynamic routes (/c/[slug], /t/[slug]/[rkey], /u/[handle]) return 404 without a running API backend, causing Lighthouse to fail. Only test static routes that render without the API.