Frontmatter support for all files

Would be great to have frontmatter for each files include in the project Markdown file, so we can include descriptions and additional instructions or context

## src/pages/api/hello.ts
[description]
[tags]

```ts
// Next.js API route support: https://nextjs.org/docs/api-routes/introduction
import type { NextApiRequest, NextApiResponse } from "next";

type Data = {
  name: string;
};

export default function handler(
  req: NextApiRequest,
  res: NextApiResponse<Data>,
) {
  res.status(200).json({ name: "John Doe" });
}

No implementation files or tests are named. Start by locating the entry point that assembles the project Markdown file and inspect how individual files are represented; then determine how frontmatter fields such as descriptions, tags, and instructions should appear for every included file. Done means generated Markdown includes the requested metadata without breaking existing file content.