Add deployment guide and fix stale README theme listing

- Create guide.md: step-by-step deployment guide in ProjectPublic
  markup format, written for non-technical users
- Add guide-format.txt: markup syntax reference
- Fix README.md: remove references to deleted templates/ and parts/
  directories in theme tree listing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

README.md

@@ -77,9 +77,8 @@ WebsiteBox uses a child theme built on [GeneratePress](https://generatepress.com
 websitebox-data/wordpress/wp-content/themes/websitebox/
 ├── style.css          # Custom styles
 ├── functions.php      # Theme functions
-├── theme.json         # Block theme settings (colors, typography)
-├── templates/         # Block templates
-└── parts/             # Template parts (header, footer)
+├── index.php          # Main template (inherits from GeneratePress)
+└── theme.json         # Theme settings (colors, typography)
 ```
 
 ### Plugins