[config] testnet.toml missing inline comment on Venus Chapel Comptroller address verification date and source

[obchain]

PR: #51 (feat/23-testnet-config)
File: config/testnet.toml (new)
Refs #51

Problem

The Venus Chapel Comptroller address 0x94d1820b2D1c7c7452A163983Dc888CEC546b77D is correct as of VenusProtocol/venus-protocol official deployments (deployments/bsctestnet/Unitroller.json, verified 2026-03-02 per PR description). Chapel contracts are redeployed during Venus protocol upgrades more frequently than BSC mainnet. Without a verification date in the TOML file, future operators cannot determine when the address was last checked.

Impact

Future deployment: address is stale, bot connects to wrong contract, all RPC calls return empty/revert, scanner produces zero positions, no error. Indistinguishable from "no liquidatable borrowers."

Fix

Add inline comment to testnet.toml:

[protocol.venus_testnet]
chain = "bnb_testnet"
# Venus Unitroller proxy on BSC testnet (Chapel)
# Source: VenusProtocol/venus-protocol deployments/bsctestnet/Unitroller.json
# Verified: 2026-03-02. Chapel contracts redeploy frequently — recheck after Venus upgrades.
comptroller = "0x94d1820b2D1c7c7452A163983Dc888CEC546b77D"

[obchain]

Fixed on feat/23-testnet-config (ea534d7): inline comment above the Chapel Comptroller address now records source (VenusProtocol/venus-protocol deployments/bsctestnet/Unitroller.json), verification date (2026-03-02), and the silent failure mode when the address goes stale.