chore: add workspace aliases to vitest config for app tests

Resolve @, @server, @getpaseo/relay, react, react-native, and xterm
ligatures from the app workspace so cross-workspace tests run.

vitest.config.ts

@@ -1,6 +1,42 @@
+import fs from "node:fs";
+import path from "node:path";
 import { defineConfig } from "vitest/config";
 
+const appDir = path.resolve(__dirname, "packages/app");
+const appNodeModules = path.resolve(appDir, "node_modules");
+const rootNodeModules = path.resolve(__dirname, "node_modules");
+const resolvePackageEntry = (packageName: string) => {
+  const appPackagePath = path.resolve(appNodeModules, packageName);
+  return fs.existsSync(appPackagePath)
+    ? appPackagePath
+    : path.resolve(rootNodeModules, packageName);
+};
+
 export default defineConfig({
+  resolve: {
+    alias: [
+      {
+        find: /^@getpaseo\/relay\/e2ee$/,
+        replacement: path.resolve(__dirname, "packages/relay/src/e2ee.ts"),
+      },
+      {
+        find: /^@getpaseo\/relay$/,
+        replacement: path.resolve(__dirname, "packages/relay/src/index.ts"),
+      },
+      { find: "@", replacement: path.resolve(appDir, "src") },
+      { find: "@server", replacement: path.resolve(__dirname, "packages/server/src") },
+      {
+        find: "react-native",
+        replacement: path.resolve(rootNodeModules, "react-native-web/dist/index.js"),
+      },
+      { find: "react", replacement: resolvePackageEntry("react") },
+      { find: "react-dom", replacement: resolvePackageEntry("react-dom") },
+      {
+        find: "@xterm/addon-ligatures",
+        replacement: path.resolve(appDir, "test-stubs/xterm-addon-ligatures.ts"),
+      },
+    ],
+  },
   test: {
     exclude: ["**/.claude/**"],
   },