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

Chicken and Pumpkin Gnocchi with Ricotta.cook

@@ -1,4 +1,3 @@
-image: https://roux.roo.lol/recipe-images/chicken-and-pumpkin-gnocchi-with-ricotta.webp
 ---
 title: Chicken & Pumpkin Gnocchi with Ricotta
 servings: 2
@@ -8,6 +7,7 @@ source: garnish-and-gather
 description: 
 prep_time: 35 minutesnutes
 totalTime: PT35M
+image: https://roux.roo.lol/recipe-images/chicken-and-pumpkin-gnocchi-with-ricotta.webp
 ---
 
 Remove any large stems from @spinach{2 1/2 cups} and roughly chop.