fix: correct YAML frontmatter, convert images to proper WebP format

- Moved image: field from outside to inside YAML frontmatter (50 files)
- Converted all 56 non-WebP images to proper WebP format via ImageMagick
- Fixed Python shebangs for portability
- Updated source fields in 2 Task 3 recipes

Alain-Ducase-Bread.cook

@@ -1,4 +1,3 @@
-image: https://roux.roo.lol/recipe-images/alain-ducase-bread.webp
 ---
 
 title: Alain Ducasse's Gougères
@@ -17,6 +16,7 @@ tags:
 
   - french
 
+image: https://roux.roo.lol/recipe-images/alain-ducase-bread.webp
 ---