Autogeneration ideas

[patroza]

related to https://github.com/Effect-TS/effect/pull/1629

• /src/index.ts generate via eslint codegen instead
• /src/*.ts generate the export declare namespace, export * from etc
• when editing/creating a /src/impl/*.ts file, generate a basic /src/*.ts file when missing
• related: post-build step to replace import { X } from "effect/X" to import * as X from "effect/X" (have to figure out multi imports eg import { X, Y }) related to https://github.com/Effect-TS/effect/pull/1633

https://www.npmjs.com/package/eslint-plugin-codegen

cc @fubhy