feat(skills): add Billions Network KYA identity bridge

[AgungPrabowo123]

What

Added a new optional skill (billions-identity) that enables Hermes Agent to authenticate and mint a Decentralized Identifier (DID) as an ERC-721 token on the Billions Network.

Why

To provide Hermes Agent with an officially verifiable on-chain identity, achieving parity with other Web3 agent frameworks. This enables the agent to securely interact with DePIN networks and smart contracts that require Know Your Agent (KYA) compliance.

How to test

1. Move the skill to the active skills directory:
   cp -r optional-skills/billions_identity ~/.hermes/skills/
2. Configure the wallet key in ~/.hermes/.env:
   WALLET_PRIVATE_KEY="0x..."
3. Navigate to the skill folder and install dependencies:
   npm install @iden3/js-iden3-auth uuid ethers shell-quote
4. Prompt Hermes via terminal/gateway to run the Billions identity generation procedure.
5. Verify the generated Base64 payload URL and confirm the DID minting on the Billions Block Explorer.

Platforms Tested

• Linux (Ubuntu / WSL2)

[AgungPrabowo123]

https://explorer.billions.network/token/0x1646a1BE735dB74562d9Aaa568188ae3413a9d34/instance/5725

[teknium1]

Thanks for the contribution! This is too niche for the repo — it's a single-vendor integration for one specific Web3 network. Skills like this are better suited for the community skills hub (ClawHub / skills.sh) where users who need Billions Network KYA compliance can discover and install it independently.

If you publish it to a skills hub, users can install it with /skills install without it needing to live in the main repo.