Restructure project directories (#333)

`/client/web` -> `/frontend`
`/client/cli` -> *delete for now*
`/client/native` -> *delete for now*
`/core/editor` -> `/editor`
`/core/document` -> `/graphene`
`/core/renderer` -> `/charcoal`
`/core/proc-macro` -> `/proc-macros` *(now plural)*

frontend/src/utilities/response-handler-binding.ts

@@ -0,0 +1,4 @@
+// This file is instantiated by wasm-bindgen in `/frontend/wasm/src/lib.rs` and re-exports the `handleResponse` function to
+// provide access to the global copy of `response-handler.ts` with its shared state, not an isolated duplicate with empty state
+
+export { handleResponse } from "@/utilities/response-handler";