Support ERC-20 token prizes (DAI) — add currency field

[oritwoen]

Context

Arweave puzzle weave9 has a prize of 100 DAI (ERC-20 token on Ethereum), not ETH. The current data model uses Chain enum to imply both the blockchain and the currency, which breaks for ERC-20 tokens — chain: "ethereum" with prize: 100 would be misread as 100 ETH.

Problem

The Chain enum serves double duty:

1. Blockchain the address lives on (Ethereum)
2. Currency of the prize (implicitly ETH for Ethereum)

For ERC-20 tokens these diverge — the address is on Ethereum but the prize is in DAI.

Proposal

Add an optional currency field to the puzzle data model:

{
  "name": "weave9",
  "chain": "ethereum",
  "currency": "dai",  // new field, defaults to chain's native token if absent
  "prize": 100,
  // ...
}

Affected files:

• src/puzzle.rs — add currency: Option<&'static str> field
• build.rs — codegen for currency field
• data/schemas/definitions.schema.json — add currency to schema
• data/arweave.jsonc — add weave9 entry with currency field
• src/cli.rs — display currency in stats/show output

Blocked puzzle

• weave9: chain Ethereum, address 0x6f85d220c70abb69a1205b96b566c1ed5d9c3831, prize 100 DAI, status claimed (2020-06-08), source https://arweave.net/1--NRFY3naNwTlxBSRjzDPNUq-Cn1yLG2RmgGHZem9c

[coderabbitai]

🔗 Related PRs

#103 - feat: add pubkey validation for claimed puzzles [merged]
#109 - refactor(chain): multichain prep [merged]

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