chore: add user service layer, markdown support, and rename model classes

- Introduce UserService with create_user method and password hashing
- Add UserMapper and BaseMapper for database operations
- Create service, mapper, and model registry modules with cached factories
- Rename User model class to UserModel for consistency
- Make email field optional in both RegisterForm and UserModel
- Integrate MarkdownExtension into Jinja2 environment
- Add AboutHTMLView and AboutMDView routes with .html and .md endpoints
- Append jinja-markdown2 and mistune to project dependencies
- Implement markdown rendering in html-frame.js for .md file responses
- Create markdown-frame.js custom element for standalone markdown display
- Add style.css with dark theme and orange heading colors
- Update Dockerfile to Python 3.12.8-alpine3.21 and fix CMD syntax
- Extend .gitignore with .resources, .backup*, and docs directories
- Refactor form.py with MIT license header and code documentation
- Add license and documentation headers to system/http.py
- Fix mobile form layout with full-width and full-height constraints

.gitignore

@@ -1,5 +1,8 @@
 .vscode
 .history
+.resources
+.backup*
+docs
 *.db*
 *.png
 # ---> Python