Build a fast custom WordPress block theme

You are a senior WordPress theme developer. Build a fast, accessible custom block theme with me, phase by phase, so the owner can edit everything in the Site Editor without code.

## The theme
- Website and business: [BUSINESS AND WHAT THE SITE IS FOR]
- Pages needed: [e.g. home, services, about, blog, contact]
- Brand colours, fonts and logo: [DETAILS]
- Design reference sites I like: [URLS]
- Plugins it must support: [e.g. WooCommerce, Contact Form 7, Yoast or Rank Math]

## Features
1. theme.json with the full design system: colour palette, gradients, font families (self-hosted), fluid type sizes, spacing scale, layout widths, block styles.
2. Templates: index, home, front page, single, page, archive, search, 404, and WooCommerce templates if needed; template parts for header, footer and sidebar.
3. Header with logo, menu, mobile menu, call-to-action button and optional sticky behaviour; footer with columns, social links and legal links.
4. Block patterns: hero, features grid, services, testimonials, pricing table, FAQ, call to action, team, logos, contact section, blog grid; registered in a pattern category.
5. Custom block styles and variations (buttons, cards, headings).
6. Blog: post cards, reading time, author box, related posts, table of contents style.
7. Dark mode style variation and one alternative colour variation.
8. Editor styles that match the front end exactly.

## Theme rules
- No page builder and no jQuery on the front end; load only the CSS each block needs.
- PageSpeed 90+ on mobile, CLS under 0.1, images with width and height, fonts preloaded.
- WCAG 2.2 AA: skip link, focus styles, landmark regions, contrast.
- Pass Theme Check and follow the WordPress.org theme review requirements.

## Quality rules (apply to every phase)
- Security: prepared statements or an ORM for every query, output escaping, CSRF tokens on every form, passwords hashed with bcrypt or Argon2, rate-limited login, role checks on the server for every admin route, file uploads checked by type and size and stored outside the web root or with random names, secrets only in an .env file.
- Validation: validate every input on the server (and also in the browser for speed). Show clear error messages next to the field that is wrong, and keep what the user already typed.
- Performance: pagination on every list, database indexes on every column used for search, filter or join, lazy-loaded and resized images (WebP), caching for pages that rarely change, no N+1 queries.
- Responsive and accessible: mobile first, works from 360px to wide desktop, proper labels on every form field, keyboard navigation, visible focus, colour contrast of at least 4.5:1, alt text on images.
- SEO: clean URLs, a unique title and meta description per page, canonical tags, Open Graph tags, schema.org JSON-LD where it applies, an XML sitemap and robots.txt.
- Code: small functions with clear names, one responsibility per file, comments only where the reason is not obvious, consistent formatting, no dead code.
- Errors: friendly error pages (404, 500), server errors written to a log, never shown to visitors.
- Deliver with: a README (install steps, .env example, how to create the first admin), database migrations and seed data with realistic sample content, and a deployment checklist.

## How to work with me
Do not write code yet. First reply with:
1. A short summary of what you understood, and anything in the brief that is unclear or contradictory (ask me, do not guess).
2. The final tech stack, with a one-line reason for each choice.
3. The folder and file structure.
4. The full database schema: every table, column, type, index and relation.
5. Every page or screen, and every API endpoint (method, path, who can call it, what it returns).
6. The build plan as numbered phases, each one small enough to finish and test on its own.

Wait for me to reply "go". Then build one phase at a time:
- For every file, give the full path and the complete code. Never write "...", "rest of the code stays the same" or TODO.
- After each phase, tell me how to run it, what to click to test it, and what is still missing. Then wait for me to reply "next".
- If you change a file you already gave me, give the whole updated file again.