refactor: move schema to config file

src/content/config.ts

@@ -1,8 +1,19 @@
-import { defineCollection } from "astro:content";
-import { blogSchema } from "./_schemas";
+import { defineCollection, z } from "astro:content";
 
 const blog = defineCollection({
-  schema: blogSchema,
+  type: "content",
+  schema: z.object({
+    author: z.string().optional(),
+    pubDatetime: z.date(),
+    title: z.string(),
+    postSlug: z.string().optional(),
+    featured: z.boolean().optional(),
+    draft: z.boolean().optional(),
+    tags: z.array(z.string()).default(["others"]),
+    ogImage: z.string().optional(),
+    description: z.string(),
+    canonicalURL: z.string().optional(),
+  }),
 });
 
 export const collections = { blog };