feat(rsc): support inline "use cache" exports in file-level "use server" modules and vice versa

[hi-ogawa]

• closes Support inline "use cache" exports in file-level "use server" modules and vice versa #1394

This PR loosens server reference claim overlap mechanism so it can support file/inline directive mixing of following with Next.js like semantics. It also adjusted use cache transform plugin in the example to take into account the same source can include use server.

'use server'

import { state } from './state'

// not cached
export async function defaultAction(_key: string) {
}

// cached
export async function overrideAction(_key: string) {
  'use cache'
}

'use cache'

import { state } from './state'

// cached
export async function defaultAction() {
}

// not cached
export async function overrideAction() {
  'use server'
}