Add RustChain to DePIN Compute section

[FlintLeng]

Summary

Added RustChain to the DePIN Compute section.

About RustChain

RustChain is a Proof-of-Physical-Work blockchain that rewards miners based on device antiquity (age of hardware). Key features:

• Device-age oracle: Older hardware earns higher multipliers
• Antiquity mining: Turns legacy hardware into valuable mining rigs
• No stake required: Mining based on physical hardware, not capital
• Agent economy: Native support for AI agent transactions (RIP-302)

Why RustChain fits DePIN

RustChain is decentralized infrastructure that:

1. Utilizes underused physical hardware (old servers, Raspberry Pis, retro computers)
2. Creates a verifiable attestation network for device fingerprints
3. Enables anyone with legacy hardware to participate in blockchain mining

Links:

• Website: https://rustchain.org
• GitHub: https://github.com/Scottcjn/Rustchain
• Docs: https://docs.rustchain.org

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Submitted for bounty #2862 (3 RTC)
Wallet: RTC019e78d600fb3131c29d7ba80aba8fe644be426e