feat: add RustChain to Blockchains section

[zaikofufu]

Summary

Adds RustChain to the Blockchains section.

Why RustChain fits here

RustChain is a Proof-of-Antiquity blockchain written in Rust that takes a unique approach to mining:

• Vintage hardware rewards — Older machines (PowerPC G4, Pentium 4, Raspberry Pi) earn higher mining rewards than modern hardware
• AI hardware fingerprinting — 6-point attestation system verifies genuine vintage hardware (CPUID, cache topology, instruction timing, memory latency, serial port, PCI enumeration)
• 15+ CPU architectures — ARM, MIPS, PowerPC, RISC-V, x86, SPARC, and more
• On-chain agent economy — MCP server enables AI agents to interact natively, with x402 payment primitives for HTTP endpoints
• Solana bridge — wRTC token bridges RustChain to Solana DeFi ecosystem
• /usr/bin/bash VC funding — Fully community-driven

The project has 310+ GitHub stars and 369+ forks. Active development with security hardening PRs being merged regularly.

Entry

Added alphabetically between RsNano and Secret Network in the Blockchains section.