refactor: update blog post date handling and schema

- Replaced `pubDate` with `datePublished` in blog post components for consistency.
- Updated sorting logic in blog sections to use `datePublished`.
- Enhanced blog post schema to include `dateModified` for better structured data representation.
- Adjusted various blog markdown files to reflect the new date fields.

src/content/config.ts

@@ -4,11 +4,12 @@ const blog = defineCollection({
 	type: "content",
 	schema: z.object({
 		author: z.string(),
+		dateModified: z.coerce.date(),
+		datePublished: z.coerce.date(),
 		description: z.string(),
 		draft: z.optional(z.boolean()),
-		pubDate: z.coerce.date(),
-		title: z.string(),
 		lang: z.string(),
+		title: z.string(),
 	}),
 });