Add support for the Sepolia testnet alongside Ethereum mainnet:
- New src/shared/networks.js with network definitions (mainnet + sepolia)
including chain IDs, default RPC/Blockscout endpoints, and explorer URLs
- State now tracks networkId; defaults to mainnet for backward compatibility
- Network selector in Settings lets users switch between mainnet and Sepolia
- Switching networks updates RPC URL, Blockscout URL, and chain ID
- All hardcoded etherscan.io URLs replaced with dynamic explorer links
from the current network config (sepolia.etherscan.io for Sepolia)
- Background handles wallet_switchEthereumChain for both supported chains
and broadcasts chainChanged events to connected dApps
- Inpage provider fetches chain ID on init and updates dynamically via
chainChanged events (no more hardcoded 0x1)
- Blockscout API uses eth-sepolia.blockscout.com for Sepolia
- Etherscan label/phishing checks use the correct explorer per network
- Price fetching skipped on testnets (tokens have no real value)
- RPC validation checks against the selected network's chain ID
- getProvider() uses the correct ethers Network for Sepolia
API endpoints verified:
- Etherscan: sepolia.etherscan.io
- Blockscout: eth-sepolia.blockscout.com/api/v2
- RPC: ethereum-sepolia-rpc.publicnode.com
closes#110
Expands the confirm-tx warning system with three new warning types, all using the existing `visibility:hidden/visible` pattern from PR #98 (no animations, no layout shift).
## Changes
1. **Scam address list expanded** (7 → 652 addresses): Sourced from [MyEtherWallet/ethereum-lists](https://github.com/MyEtherWallet/ethereum-lists) darklist (MIT license). Checked synchronously before sending.
2. **Contract address warning**: When the recipient is a smart contract (detected via `getCode`), shows a warning that sending directly to a contract may result in permanent loss of funds.
3. **Null/burn address warning**: Detects known burn addresses (`0x0000...0000`, `0x...dead`, `0x...deadbeef`) and warns that funds are permanently destroyed.
4. **No-history warning** (existing from #98): Unchanged, still shows for EOAs with zero transaction history.
All warnings use reserved-space `visibility:hidden/visible` elements — no layout shift, no animations.
closes#114
Co-authored-by: clawbot <clawbot@noreply.git.eeqj.de>
Co-authored-by: user <user@Mac.lan guest wan>
Co-authored-by: clawbot <clawbot@eeqj.de>
Reviewed-on: #118
Co-authored-by: clawbot <sneak+clawbot@sneak.cloud>
Co-committed-by: clawbot <sneak+clawbot@sneak.cloud>
