refactor(react-server): simplify route tree utils (#338)

Picking up some code from
- #257

Preparing for
- #337

The idea is to extract routing logic (fs route tree generation + route matching) out of react-server world, so it can be used anywhere as a pure utility. This also helps test-ability.

packages/react-server/examples/basic/e2e/basic.test.ts

@@ -870,7 +870,7 @@ testNoJs("catch-all routes @nojs", async ({ page }) => {
   await testCatchallRoute(page, { js: false });
 });
 
-async function testCatchallRoute(page: Page, options: { js: boolean }) {
+async function testCatchallRoute(page: Page, _options: { js: boolean }) {
   await page
     .getByRole("link", { name: "• /test/dynamic/catchall/static" })
     .click();
@@ -904,10 +904,8 @@ async function testCatchallRoute(page: Page, options: { js: boolean }) {
     .click();
   await page.getByText("file: /test/dynamic/catchall").click();
   await page.getByText('params: {"any":"x/y/w"}').click();
-  // state is preserved
-  await expect(page.getByLabel("test state")).toBeChecked({
-    checked: options.js,
-  });
+  // state is not preserved
+  await expect(page.getByLabel("test state")).not.toBeChecked();
 }
 
 test("full client route", async ({ page }) => {

packages/react-server/src/entry/react-server.tsx

@@ -28,7 +28,7 @@ import {
   createError,
   getErrorContext,
 } from "../lib/error";
-import { generateRouteTree, renderRouteMap } from "../lib/router";
+import { generateRouteModuleTree, renderRouteMap } from "../lib/router";
 
 const debug = createDebug("react-server:rsc");
 
@@ -147,7 +147,7 @@ function createRouter() {
       eager: true,
     },
   );
-  const tree = generateRouteTree(
+  const tree = generateRouteModuleTree(
     objectMapKeys(glob, (_v, k) => k.slice("/src/routes".length)),
   );