Merge hero redesign into main and document main-only Pages deployment

[becktothefuture]

Motivation

• Bring the new hero redesign and related site updates from the work branch into the primary branch so the live site can serve the updated landing experience.
• Ensure the GitHub Pages workflow continues to trigger from the branch used for production deploys.
• Make the deployment policy explicit in repository docs so contributors know which branch is authoritative.

Description

• Merged the hero redesign and supporting asset/layout changes into main, including large updates to src/App.jsx, src/styles.css, theme files, components, and public assets.
• Added (or preserved) the GitHub Actions Pages workflow at .github/workflows/deploy-pages.yml configured to trigger on push/pull_request targeting main and to run the deploy job only for refs/heads/main.
• Added README.md with a short deployment note: "Live site deploys from main only."
• Kept the build and tooling changes required by the redesign (theme token generation and asset pipeline scripts) so npm run build produces a production dist bundle.

Testing

• Confirmed hero-related history with git log --oneline -- src/App.jsx src/styles.css, which showed the redesign commits present. (succeeded)
• Ran a production build with npm ci && npm run build, which completed successfully and produced a dist output. (succeeded)
• Attempted to push main with git push -u origin main, but the push failed due to no origin remote configured in this environment, so GitHub Actions/Pages run creation could not be verified here. (failed due to environment)

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Codex Task

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Add required tool/output framing to README intro

The new README intro doesn’t satisfy the mandatory copy requirements in /workspace/Explainitlikeim/AGENTS.md and /workspace/Explainitlikeim/COPY_RULES.md: supporting copy must explicitly say this skill can be used in tools like Codex, Claude Code, and Cursor, and must state that it rewrites one answer into five levels. Right now it only says “a skill for AI agents,” so first-time readers miss required product context and the commit violates the project’s non-negotiable framing rules.

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