Update ZK-proof guide (Circom + Groth16) for TON

[mysteryon88]

Description

• Updated Circom + Groth16 guide for TON
• Added relevant links in sidebar navigation

Closes <--link to issue]-->.

Checklist

• [ ] I have created an issue.
• [x] I am working on content that aligns with the Style guide.
• [x] I have reviewed and formatted the content according to Content standardization.
• [x] I have reviewed and formatted the text in the article according to Typography.