Convert blog posts from .md to .mdoc format for KeyStatic

- Convert all 32 blog posts to .mdoc format
- Add content.config.ts to handle .mdoc files in Astro
- This allows KeyStatic to find and manage the blog posts

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

src/content.config.ts

@@ -0,0 +1,20 @@
+import { defineCollection, z } from 'astro:content';
+import { glob } from 'astro/loaders';
+
+const post = defineCollection({
+  loader: glob({ pattern: '**/*.mdoc', base: './src/data/post' }),
+  schema: z.object({
+    title: z.string(),
+    date: z.date(),
+    author: z.string().default('TA1SPH'),
+    categories: z.array(z.string()).default([]),
+    tags: z.array(z.string()).default([]),
+    layout: z.string().default('post'),
+    image: z.string().optional(),
+    excerpt: z.string().optional(),
+  }),
+});
+
+export const collections = {
+  post,
+};