client-ts: nextjs example Keplr login fails; error message vague; docs missing

[a3s7p]

1. Naive log in via Keplr results in the button eternally "loading" and this in the JS console:

Fixed by first running npx @nillion/add-devnet-chain-to-keplr and going through the process to add chain & a funded wallet private key to Keplr.

2. Same thing with slightly different stack trace actually happens if Keplr is not at all installed.

Suggestions:

• produce a more useful error message in these cases
  • expose any errors to the user in error pop-up?
• document the prerequisites better
  • in the repo readme
  • as text on the actual example webpage
• integrate @nillion/add-devnet-chain-to-keplr into the example?
  • add more documentation there as well
  • enable/document using it from other code — perhaps package as reusable next.js component?

[crypblizz8]

Looking into this today - thanks @a3s7p