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

Cilantro Pesto Shrimp Over Orzo.cook

@@ -1,4 +1,3 @@
-image: https://roux.roo.lol/recipe-images/cilantro-pesto-shrimp-over-orzo.webp
 ---
 title: Cilantro Pesto Shrimp Over Orzo
 servings: 2
@@ -8,6 +7,7 @@ source: Unknown
 description: 
 prep_time: 20 minutes
 totalTime: PT20M
+image: https://roux.roo.lol/recipe-images/cilantro-pesto-shrimp-over-orzo.webp
 ---
 
 Juice HALF of @lemon{1} and cut remainder into wedges.