Build a custom WordPress plugin the right way

You are a senior WordPress developer who has published plugins on WordPress.org. Build a complete, secure WordPress plugin with me, phase by phase, following the WordPress Coding Standards.

## The plugin
- Plugin name: [PLUGIN NAME]
- What it does in one sentence: [WHAT IT DOES]
- Who uses it: [SITE OWNERS / EDITORS / VISITORS]
- Minimum versions: WordPress [VERSION], PHP [VERSION]
- Free, freemium or paid: [MODEL]
- Must work with: [e.g. WooCommerce, Elementor, multisite]

## Features
1. Plugin structure: main file with header, a namespaced class-based structure, autoloading, activation, deactivation and uninstall hooks (uninstall removes options and tables only if the user chose that).
2. Settings page under the right admin menu using the Settings API, with sections, fields, sanitisation callbacks and a help tab.
3. Data: custom post types and taxonomies or custom tables (created with dbDelta) for [WHAT IT STORES], with admin list columns, filters and bulk actions.
4. Front end: a Gutenberg block and a shortcode for [WHAT IT DISPLAYS], with block attributes, editor preview and server-side rendering.
5. REST API routes under its own namespace with permission callbacks, and AJAX actions with nonces.
6. Email or admin notices where needed, dismissible and shown only to the right users.
7. Translation-ready: text domain, .pot file, all strings wrapped.
8. Assets: scripts and styles enqueued only on the pages that need them.
9. Import and export of settings as JSON.
10. A readme.txt in WordPress.org format, with screenshots list, FAQ and changelog.

## WordPress rules
- Check capabilities (current_user_can) and nonces on every form, AJAX call and REST route; sanitise all input and escape all output (esc_html, esc_attr, wp_kses).
- Use $wpdb->prepare for every custom query; never trust $_GET or $_POST directly.
- Prefix every function, option, hook and CSS class to avoid conflicts; add actions and filters so other developers can extend it.
- Pass the Plugin Check plugin and PHPCS with the WordPress standard.

## 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.