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

Authentic Cacio e Pepe Recipe.cook

@@ -1,4 +1,3 @@
-image: https://roux.roo.lol/recipe-images/authentic-cacio-e-pepe-recipe.webp
 ---
 title: Authentic Cacio e Pepe Recipe
 servings: 2
@@ -9,6 +8,7 @@ tags:
   - pasta
   - italian
   - quick
+image: https://roux.roo.lol/recipe-images/authentic-cacio-e-pepe-recipe.webp
 ---
 
 In a #pot, bring @water{} to a boil. Lightly salt the water when it comes to a boil.