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

Spaghetti_Squash_w_Chickpeas_and_Kale.cook

@@ -1,9 +1,9 @@
-image: https://roux.roo.lol/recipe-images/spaghetti-squash-w-chickpeas-and-kale.webp
 ---
 title: Spaghetti Squash w/ Chickpeas & Kale
 servings: 3
 category: Main
 source: Love and Lemons
+image: https://roux.roo.lol/recipe-images/spaghetti-squash-w-chickpeas-and-kale.webp
 ---
 Preheat the oven to 400F.
 Prepare your squash following the directions in this post.