Devtools can have a "stores" tab

Spruce has a methods (outside of Alpine) for:

• accessing stores: https://docs.ryangjchandler.co.uk/spruce/stores#accessing-a-store-from-javascript
• set data in store: https://docs.ryangjchandler.co.uk/spruce/stores#overwriting-a-store
• watching a store: https://docs.ryangjchandler.co.uk/spruce/watchers
• listing stores with Object.keys(Spruce.stores)

("stores" > "spruce" so that we're forward compatible if stores make it into v3)

Originally posted by @HugoDF in #175