feat: complete section color coding with logo, hints, editor themes, and footers

- Add section-specific CodeMirror syntax highlighting (purple selectors for CSS)
- Logo now uses section colors (CSS purple as default, changes per section)
- Add section color coding for hints
- Add full footer to section and reference pages
- Fix nav highlight updates for sidebar and prev/next navigation
- Change welcome module mode to CSS for purple theme on first lesson
- Rebrand "Code Crispies" to "CODE CRISPIES" across all translations
- Fix scroll to top on section page navigation
- Change HTML section color to raspberry (#c75b7a)

lessons/uk/00-welcome.json

@@ -3,7 +3,7 @@
 	"id": "welcome",
 	"title": "Ласкаво просимо",
 	"description": "Почніть з Code Crispies",
-	"mode": "html",
+	"mode": "css",
 	"difficulty": "beginner",
 	"excludeFromProgress": true,
 	"lessons": [