✨ feat: add new contact form, hero, features, and richtext blocks; implement scroll-reveal action and update styles

- Introduced ContactFormBlock, FeaturesBlock, HeroBlock, and RichtextBlock components.
- Implemented a scroll-reveal action for animations on element visibility.
- Enhanced CSS styles for better theming and prose formatting.
- Added localization support for new components and updated existing translations.
- Created e2e tests for demo pages including contact form validation and navigation.
- Added a video tour showcasing the demo pages and interactions.

types/global.d.ts

@@ -83,12 +83,16 @@ interface ContentBlockEntry {
     }
     heroImage?: {
         image?: string
+        /** External image URL (e.g. Unsplash) — used when no medialib ID is available */
+        externalUrl?: string
     }
     // richtext fields
     text?: string
     imagePosition?: "none" | "left" | "right"
     imageRounded?: string
     image?: string
+    /** External image URL for richtext/generic blocks (e.g. Unsplash) */
+    externalImageUrl?: string
     // accordion fields
     accordionItems?: {
         question?: string