Add paragraph spacing to prose content styling

Add proper margin (my-4) to paragraphs in Tiptap-rendered content.
This ensures proper spacing between paragraphs when displaying
rich text content in product detail pages and other areas.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/index.css

@@ -180,6 +180,11 @@ All colors MUST be HSL.
     @apply text-lg font-bold mt-4 mb-2;
   }
 
+  /* Paragraphs */
+  .prose p {
+    @apply my-4;
+  }
+
   /* Lists */
   .prose ul {
     @apply list-disc pl-6 space-y-1 my-4;