test: resolve nest packages from this checkout in integration tests

The @nestjs/* packages installed from npm (graphql, apollo, mongoose,
typeorm) import @nestjs/core and @nestjs/common from where they are
installed. When node_modules is linked to another checkout, as in a git
worktree that shares the main checkout's node_modules, that is a second
copy of every class. Dependency injection then failed (GraphQLModule
could not resolve HttpAdapterHost), so every graphql-schema-first spec
failed in such a checkout while CI passed.

The integration config now dedupes the packages of this repository, so
Vite resolves them from the project root whoever imports them. Nothing
changes where node_modules is installed in place.

vitest.config.integration.mts

@@ -73,5 +73,22 @@ export default defineConfig({
     reporters: ['default'],
     fileParallelism: false,
   },
+  resolve: {
+    // The @nestjs/* packages that live in node_modules import the packages of
+    // this repository from where they are installed. When node_modules is
+    // linked to another checkout (e.g. in a git worktree), that is a second
+    // copy of every class (HttpAdapterHost), so they are resolved from here.
+    dedupe: [
+      '@nestjs/common',
+      '@nestjs/core',
+      '@nestjs/microservices',
+      '@nestjs/platform-express',
+      '@nestjs/platform-fastify',
+      '@nestjs/platform-socket.io',
+      '@nestjs/platform-ws',
+      '@nestjs/testing',
+      '@nestjs/websockets',
+    ],
+  },
   plugins: [resolveTypescriptSource()],
 });