Clarify local dev workflow

[grod220]

We have this in the readme:

https://github.com/prax-wallet/web/blob/75acabe947115b21c946eb04519608c190f168b9/README.md?plain=1#L78-L92

But also have:

• add-tgz.ts
• watch-and-repack.sh

For a dev that hasn't done Prax-Minifront local development, it's not super clear what is the canonical way to do this.

Task:

• Write detailed docs on how local development is done between the two repos (prax-wallet/web & penumbra-zone/web). Enumerate all the steps specifically that needs to be done as if a newbie was doing this.
• Remove scripts (if not core to the dev process)

[turbocrime]

scripts/add-tgz.ts provides the add:tgz package script.

watch-and-repack has problems and should be considered obsolete, but it was not removed by request.

todo: remove watch-and-repack.sh