Add support for future.unstable_passThroughRequests

[brophdawg11]

RFC: #14505

This is a standalone RFC, but it's being driven by the Observability RFC because it will allow users to differentiate document from data requests in their instrumentation layers.

Currently, we strip .data suffixes, ?index search params and ?_routes search params from the request.url passed to loaders, actions, middleware. This means we incur some minor overhead to create a few new Request instances during server side processing.

With this new future flag, we will stop altering the request and pass it to you as-is. To preserve the "location the application is at" (what the mutated request.url represents today), we're adding a sibling unstable_path parameter.

// GET Document requests aren't impacted
// Assume user loaded /a/b/c?k=v in their browser
export function loader({ request, unstable_path }) {
  // previous request -> GET https://example.com/a/b/c?k=v
  // new request -> GET https://example.com/a/b/c?k=v
  // new unstable_path = { pathname: "/a/b/c", search: "?k=v", hash: "" }  
}

// Submission requests are if you performed a document request submission to an index route
// Assume POST /a/b/c?index
export function loader({ request, unstable_path }) {
  // previous request -> POST https://example.com/a/b/c
  // new request -> POST https://example.com/a/b/c?index
  // new unstable_path = { pathname: "/a/b/c", search: "", hash: "" }  
}

// Data requests are also impacted
// Assume user navigated to /a/b/c?k=v in their browser
export function loader({ request, unstable_path }) {
  // previous request -> GET https://example.com/a/b/c?k=v
  // new request -> GET https://example.com/a/b/c.data?k=v
  // unstable_path = { pathname: "/a/b/c", search: "?k=v", hash: "" }  
}

// Data requests are also impacted
// Or is doing granular revalidation and only revalidating the root route with _routes=root
export function loader({ request, unstable_path }) {
  // previous request -> GET https://example.com/a/b/c?k=v
  // new request -> GET https://example.com/a/b/c.data?k=v&_routes=root
  // unstable_path = { pathname: "/a/b/c", search: "?k=v", hash: "" }  
}

[changeset-bot]

🦋 Changeset detected

Latest commit: 3d17cf5

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 11 packages

Name	Type
@react-router/dev	Patch
react-router	Patch
@react-router/fs-routes	Patch
@react-router/remix-routes-option-adapter	Patch
@react-router/architect	Patch
@react-router/cloudflare	Patch
react-router-dom	Patch
@react-router/express	Patch
@react-router/node	Patch
@react-router/serve	Patch
create-react-router	Patch

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[brophdawg11]

There is no client-side middleware future flag since it was an opt-in API, so this wasn't doing anything