Deploy a testnet contract & UI for testing

[luxumbra]

Is your feature request related to a problem? Please describe.
Often I will want to test an NFT or something without it showing up on the main contract in OpenSea and such. I would love to be able to mint test NFTs to testnet before I create the final production copy that will be sent out.

Describe the solution you'd like
Deploy a clone of the UI which uses a contract deployed on testnet.

Describe alternatives you've considered
Not really sure if there is an alternative. Happy to go with what others think is best but would like some ability to run tests and to not have to put everything on mainnet polygon.

[dysbulic]

There should be one deployed to Mumbai at 0x127B81AF011a2DF44F933b2b09c655D59Bb57b3C. There's not a running server for it, but you could see it locally.

I'll see if I can find the seed phrase for upgrading it.

There is an environment variable CHAIN_NAME (& VITE_CHAIN_NAME for the UI) that determines where assets are stored that are generated by the contract deployment. It also affects where the UI looks for the contract.