docs: standardise README and add docs/

[willtheorangeguy]

Brings willtheorangeguy.github.io in line with the Wave 2 documentation contract.

Read this first: src/pages/projects.astro hardcodes image URLs into other repositories' docs/images/ directories, which this sweep is deleting in favour of willtheorangeguy/.github/icons/. One of those images is already broken and twelve more break as the other open PRs merge. Every replacement already exists centrally. Details and the full list are in docs/internal/known-issues.md; nothing in src/ is changed here.

README — rewritten to the house template. The logo used a github.com/.../blob/ URL, which serves an HTML page rather than image bytes, so the repository's front page opened with a broken image; both images now come from .github/icons/. The Discord badge and link are dropped, and ## Changelog and ## You may also like... are removed.

docs/ — README.md (index), quickstart.md, installation.md, usage.md (renamed from USAGE.md and rewritten around writing posts rather than only running the site), configuration.md, architecture.md, development.md, deployment.md, faq.md, troubleshooting.md, roadmap.md, and internal/known-issues.md. google-maps-automation.md is kept as it was.

• docs/images/ is removed — both files already exist in .github/icons/willtheorangeguy.github.io/.
• docs/google-maps-stats.md was a tracked empty file, written by nothing and linked from nowhere. Deleted.
• docs/legal/PRIVACY.md and TERMS.md are renamed to lowercase, and their Contact Us links given a scheme — both read ](github.com/...), which Markdown resolves as a relative path, so the one link a reader follows to make a data request was a 404.

Findings — eight, recorded in docs/internal/known-issues.md:

• The Projects page points at other repositories' docs/images/ (High), with the per-repository status listed.
• The documented docker run -p 8000:80 maps a port nothing listens on (Medium) — nginx/nginx.conf has listen 8080.
• The README logo used a blob/ URL (Medium). Corrected.
• Two lockfiles are committed and only pnpm's governs CI (Medium), while the Dockerfile runs an unlocked npm install.
• docs/google-maps-stats.md was a tracked empty file (Low). Deleted.
• CLAUDE.md describes a build pipeline missing the Storybook step and calls the site Astro 6 where package.json pins Astro 7 (Low).
• PLANNING.md is a three-line stub pointing at retired classic Projects (Low).
• The legal documents' contact links had no scheme (Low). Corrected.