feat: add Markdown learning module with 8 beginner lessons

- Add markdown-basics module with lessons for headings, text formatting,
  lists, links, and inline code
- Integrate markdown section with blue color theme (#5b8dd9)
- Add markdown mode support in CodeEditor and LessonEngine
- Add markdown preview rendering using marked library
- Add section overview page with educational content
- Add markdown reference page with syntax guide
- Add i18n translations for 6 languages (EN, DE, PL, ES, AR, UK)
- Update router to recognize #markdown as section route
- Add all section-specific CSS styles for markdown theme

schemas/code-crispies-module-schema.json

@@ -19,8 +19,8 @@
 		},
 		"mode": {
 			"type": "string",
-			"enum": ["css", "tailwind", "html"],
-			"description": "Whether this module teaches CSS, Tailwind, or HTML"
+			"enum": ["css", "tailwind", "html", "markdown"],
+			"description": "Whether this module teaches CSS, Tailwind, HTML, or Markdown"
 		},
 		"difficulty": {
 			"type": "string",
@@ -60,7 +60,7 @@
 					},
 					"mode": {
 						"type": "string",
-						"enum": ["css", "tailwind", "html"],
+						"enum": ["css", "tailwind", "html", "markdown"],
 						"description": "Override module mode for individual lessons"
 					},
 					"tailwindConfig": {