Primer branding: use sentence case for header and CTA copy

[github-actions]

What changed

Voice and tone

• src/index.html: changed the header subtitle from "Add Agentic Automation to your Repository in minutes" to "Add agentic automation to your repository in minutes".
• src/index.html: changed the primary CTA label from "Create Your Agentic Workflow" to "Create your agentic workflow".
• Updated the two Playwright e2e specs (test/e2e/smoke.spec.js, test/e2e/web-llm.spec.js) that locate the CTA by its accessible name, so they keep passing against the new copy.

Brand guidance that motivated this change

Every Primer Brand (@primer/react-brand) component example I retrieved via the primer-brand MCP server (Button, Hero, CTA banner, CTA form, Card) uses sentence case for interactive and heading text — e.g. the canonical Button example reads Primary action, not Primary Action. The two strings above were the only Title Case instances in the markup (confirmed via a full scan with grep -noE '>[A-Z][a-z]+ [A-Z][a-z]+[^<]*<'), and they were inconsistent with the rest of the site's own established sentence-case convention (e.g. "Copy prompt", "Got it", "Report an issue", "Run evals"). This was the most clear-cut, lowest-risk deviation found.

Audit notes — deviations considered but not changed

• Color: Confirmed computed WCAG contrast ratios for every custom color token in src/styles/style.css (light + dark mode): body text, muted text, accent-blue links, and all six label colors (--label-blue/purple/green/orange/pink/gray) pass AA (ratios 4.67–17.04, lowest being --label-green on white at 5.08:1 — still above the 4.5:1 AA text threshold). No contrast violations found, so no color changes were made.
• Typography: Primer Brand's Heading/Text components use lighter display weights (~440–480) for marketing headings, versus this site's bold (700) weights for h1 and step/status labels. I did not change this: the site is a product-like wizard UI (progress steps, GitHub-style labels) rather than a marketing page built from Brand Hero/Heading components, so bold condensed UI labels are the appropriate pattern here (consistent with GitHub's own product issue/PR label treatment), not a deviation from Brand's marketing-page type scale.
• Component architecture: primer_brand_review flagged that no @primer/react-brand components are used and suggested rebuilding with them. Per the task's explicit constraints, I did not restructure the page or swap @primer/css for @primer/react-brand — this repo intentionally uses Primer's product CSS, not the Brand marketing component library.
• Spacing/gradients: Reviewed --radius-md/--radius-lg (mapped to --borderRadius-medium/-large, 8px/12px) and the existing landing-page radial gradient/shine accents — all derive from this site's own accent-blue token family and pass contrast, so left untouched per the "tasteful shine is allowed" guidance.

Verification

• npm test — 329/329 tests passed (19 test files), including the updated e2e specs' accessible-name assertions.
• npm run build — build succeeded (Vite), producing dist/ without errors.

No other files were changed. No application logic, ARIA attributes, or file structure were modified.

Warning

Firewall blocked 2 domains

The following domains were blocked by the firewall during workflow execution:

• registry.npmjs.org
• unpkg.com

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "registry.npmjs.org"
    - "unpkg.com"

See Network Configuration for more information.

Generated by Primer Branding · copilot · auto · 180.2 AIC · ⌖ 8.9 AIC · ⊞ 9.5K · ◷