Exclude AppleDouble companions from test discovery (#11)

vite.config.ts

@@ -1,6 +1,6 @@
 import { readFileSync } from "node:fs";
 import path from "node:path";
-import { defineConfig } from "vitest/config";
+import { configDefaults, defineConfig } from "vitest/config";
 import react from "@vitejs/plugin-react";
 // @ts-expect-error Shared Node HTTP middleware also serves production bundles.
 import { createBundledContentHandler } from "./server/bundled-content.mjs";
@@ -119,6 +119,11 @@ export default defineConfig(({ mode }) => {
     test: {
       environment: "node",
       include: ["src/**/*.test.ts"],
+      exclude: [
+        ...configDefaults.exclude,
+        "**/._*",
+        "**/._*/**",
+      ],
       maxWorkers: 4,
     },
   };