[BUG] metadata parser is out of spec

[andoriyu]

Describe the bug
According to language spec metadata written as a YAML block in header separated by --- on top and bottom. However, right now parser expects >> style metadata.

To Reproduce

Pass this to parser:

---
title: Neutral Roast Beef (Instant Pot)
tags:
  - beef
  - instant pot
  - meal prep
---

Rub @beef roast{5 lb} with @olive oil{2 tbsp}, @salt{1 tbsp}, @black pepper{1 tbsp}, @garlic powder{1 tsp}, and @onion powder{1 tsp}.```

**Expected behavior**

Metadata correctly parsed.

**Screenshots**

Right now its parsed like this:

<img width="643" alt="Image" src="https://github.com/user-attachments/assets/82457ff6-282b-485d-8a21-ec448bcb2b09" />

**Additional context**

[dfego]

Hi there! The typescript parser is in fact out of date. There is an effort that has been discussed in #31 and started #27 to have the typescript parser be a wrapper around the canonical Rust parser so it can more easily stay up to date.

[andoriyu]

I saw, it's a good idea. I'd wait for wasm components model tho. It will make this much easier. I guess I will throw a quick wrapper with neon-rs in meanwhile.

[dfego]

I'm not sure any of us working on this at the present time are experts in this area. If you're interested in contributing either code or knowledge, it would be welcomed!

[ainesophaur]

@dfego are you only looking for contributions with regard to a wasm implementation? At quick glance, the kotin parser seems to call rust where the swift parser doesn't like this library. I'm interested in contributing to cooklang-ts to bring it up to spec but it wouldn't be a wasm implementation.