refactor "notes" into "posts" (only on the backend)

types/post.d.ts

@@ -0,0 +1,25 @@
+import type { MDXRemoteSerializeResult } from "next-mdx-remote";
+
+export type PostFrontMatter = {
+  slug: string;
+  permalink: string;
+  date: string;
+  title: string;
+  htmlTitle?: string;
+  description?: string;
+  image?: string;
+  tags?: string[];
+  noComments?: boolean;
+};
+
+export type PostWithSource = {
+  // yaml metadata
+  frontMatter: PostFrontMatter;
+
+  // the final, compiled JSX by next-mdx-remote; see lib/helpers/posts.ts
+  source: Partial<Pick<MDXRemoteSerializeResult<Record<string, never>, Record<string, never>>>>;
+};
+
+export type PostsByYear = {
+  [year: string]: PostFrontMatter[];
+};