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

Indian Spiced Chicken.cook

@@ -1,4 +1,3 @@
-image: https://roux.roo.lol/recipe-images/indian-spiced-chicken-2.webp
 ---
 title: Indian Spiced Chicken with Creamy Tomato Sauce & Spinach
 servings: 2
@@ -8,6 +7,7 @@ source: Unknown
 description: 
 prep_time: 20 minutes
 cook_time: 20 minutes
+image: https://roux.roo.lol/recipe-images/indian-spiced-chicken-2.webp
 ---
 
 Bring 1 1/2 cups @water{} & @salt{1/4 tsp} to a boil in a #pot{}.