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

West African Peanut Chicken.cook

@@ -1,4 +1,3 @@
-image: https://roux.roo.lol/recipe-images/west-african-peanut-chicken.webp
 ---
 title: West African Peanut Chicken
 servings: 2
@@ -8,6 +7,7 @@ source: Unknown
 description: 
 prep_time: 25 minutes
 cook_time: 25 minutes
+image: https://roux.roo.lol/recipe-images/west-african-peanut-chicken.webp
 ---
 
 Mince @fresno pepper{1}—remove seeds and use only half for less heat.