refactor: embrace scope cleanup, restructure code

pkgs/vide-charm/src/init.luau

@@ -0,0 +1,22 @@
+local Charm = require(script.Parent.Charm)
+local Vide = require(script.Parent.Vide)
+
+local subscribe = Charm.subscribe
+local source = Vide.source
+local cleanup = Vide.cleanup
+
+--[=[
+	Subscribes to the state of an atom and returns a Vide source.
+	
+	@param callback The atom or selector to subscribe to.
+	@return The reactive source.
+]=]
+local function useAtom<State>(callback: () -> State): () -> State
+	local state = source(callback())
+	cleanup(subscribe(callback, state))
+	return state
+end
+
+return {
+	useAtom = useAtom,
+}