fix(extraction): a file-based router reads only its own app in a monorepo (#2129)

create-t3-turbo, tamagui's starter and react-native-reusables keep an Expo
app beside a Next.js app. Expo Router read the Next app's `app/` folder as
its own, so `layout.tsx` became a `/layout` screen, `page.tsx` a `/page`
one, `_components/posts.tsx` and `api/auth/[...all]/route.ts` screens too,
and a shared `packages/app/` library's files became screens as well.

A resolver can now name `appDependencies`; its extractor runs on a file
only when that file's package.json or an enclosing one declares one of
them. When no manifest in the project declares any, detection found the
framework by other evidence and it runs everywhere, as before. Expo Router
names `expo-router`, Next.js `next`.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

src/resolution/frameworks/expo-router.ts

@@ -713,6 +713,7 @@ function scoreMatch(href: string[], route: string[]): number | null {
 export const expoRouterResolver: FrameworkResolver = {
   name: 'expo-router',
   languages: [...ROUTE_LANGUAGES],
+  appDependencies: ['expo-router'],
 
   detect(context: ResolutionContext): boolean {
     if (dependsOn(context, 'expo-router')) return true;

src/resolution/frameworks/nextjs.ts

@@ -222,6 +222,7 @@ export function nextNavVerb(name: string): string | null {
 export const nextjsResolver: FrameworkResolver = {
   name: 'nextjs',
   languages: [...ROUTE_LANGUAGES],
+  appDependencies: ['next'],
 
   detect(context: ResolutionContext): boolean {
     if (dependsOn(context, 'next')) return true;

src/resolution/types.ts

@@ -239,6 +239,16 @@ export interface FrameworkResolver {
   name: string;
   /** Languages this framework applies to. If omitted, applies to all languages. */
   languages?: Language[];
+  /**
+   * Packages an app declares when it is built on this framework. When set,
+   * `extract()` runs only on files of an app whose package.json — the file's
+   * own or an enclosing one — declares one of them: in a monorepo with an Expo
+   * app beside a Next.js app, Expo Router must not read the Next app's
+   * `app/layout.tsx` as a `/layout` screen. When no manifest in the project
+   * declares any, detection found the framework by other evidence and the
+   * extractor runs on every file, as before.
+   */
+  appDependencies?: readonly string[];
   /** Detect if project uses this framework (project-level, called once at startup) */
   detect(context: ResolutionContext): boolean;
   /** Resolve a reference using framework-specific patterns */