Pull `underlyingAddress` from on-chain via `vault.asset()` instead of canonical JSON

Each entry in `cyclo.sol/canonical/cyclo-site-tokens.json` carries the underlying ERC20 address as `underlyingAddress`. The vault implements ERC4626's `asset()` accessor that returns this same address — read it via `readContract({ functionName: 'asset' })` keyed by `(chainId, vaultAddress)`, cache, and drop the `underlyingAddress` field from the canonical JSON. Once the `underlying*` fields are all on-chain, the only thing left in the JSON is the vault address + chain.

Start with cyclo.sol/canonical/cyclo-site-tokens.json and find the code that reads each vault entry. Trace the readContract({ functionName: 'asset' }) path and its cache, keyed by chainId and vaultAddress. Done means underlyingAddress is removed from the canonical JSON and the underlying asset address is retrieved on-chain and cached.

Written by the indexing model from the issue text.