Develop a Dapp Browser to allow accounts to interact with dapps in an iframe

[johnson86tw]

• The interface is initialized, but the communication part hasn’t been implemented yet. See https://testnet.samanager.xyz/11155111/browser
• We can't inject an EIP-6963 provider into iframe-based websites, and there’s no public communication protocol for injecting a provider from an iframe parent to a dapp child page. So we use the safe-apps-sdk for communication. This browser will only support dapps integrated with Safe Apps.
• For implementation details, see Impersonater,

[johnson86tw]

Done #16