feat: add toncoin processing

[Kaladin13]

Closes #204

[github-actions]

To fix the formatting issues:

1. Install necessary dependencies: npm ci
2. Then, run this command:

npx remark -o --silent --silently-ignore payments/toncoin.mdx 

[github-actions]

To fix the formatting issues:

1. Install necessary dependencies: npm ci
2. Then, run this command:

npx remark -o --silent --silently-ignore payments/toncoin.mdx 

[Kaladin13]

/review

[github-actions]

Thanks for the thoughtful update — I left a couple of suggestions in payments/toncoin.mdx; please apply the inline suggestions.

[github-actions]

To fix the formatting issues:

1. Install necessary dependencies: npm ci
2. Then, run this command:

npx remark -o --silent --silently-ignore payments/toncoin.mdx 

[github-actions]

Thanks for the update. In payments/toncoin.mdx, a couple of suggestions to align safety callouts—please apply the inline suggestions.

[github-actions]

To fix the formatting issues:

1. Install necessary dependencies: npm ci
2. Then, run this command:

npx remark -o --silent --silently-ignore payments/toncoin.mdx 

[github-actions]

To fix the formatting issues:

1. Install necessary dependencies: npm ci
2. Then, run this command:

npx remark -o --silent --silently-ignore payments/toncoin.mdx 

[anton-trunov]

Great content!

A couple of points, though:

• looks like we should recommend the unique deposit address as the go-to solution;
• we need to include a subsection on what NOT to do when doing Toncoin processing: one thing that comes to mind is "do not send funds to nonexistent accounts without making sure you can later deploy a contract at that address, otherwise you will freeze those money in that uninit account"; is there anything else to warn against?

[github-actions]

To fix the formatting issues:

1. Install necessary dependencies: npm ci
2. Then, run this command:

npx remark -o --silent --silently-ignore payments/toncoin.mdx 

[github-actions]

Thanks for the PR—spotted a couple of style issues in payments/toncoin.mdx; please apply the inline suggestions.