deploy --watch

[dckc]

Many tools have a --watch mode that somehow notices every time you change a relevant file.

Use the same technique, and re-deploy on each change.

p.s. this is a substantial project. before we get into this, there's some low hanging fruit:

• emphasize unit testing yarn test --watch for troubleshooting documentation#1189

[dckc]

Sometimes redeploying requires restarting the chain; for example, if you're trying to put something in the vbank, you irreversibly use up names when you do so. How to manage expectations around that?

• issue a warning of some sort?