Add napcat-test package and Vitest setup

Introduces the napcat-test package with initial SHA-1 stream tests, configuration files, and scripts for running tests. Updates root package.json to include test commands and Vitest dependencies, and adds Vitest configuration at the root and package level for test environment setup.

vitest.config.ts

@@ -0,0 +1,15 @@
+import { defineConfig } from 'vitest/config';
+import { resolve } from 'path';
+
+export default defineConfig({
+  test: {
+    environment: 'node',
+    globals: true,
+    include: ['packages/napcat-test/**/*.test.{js,mjs,cjs,ts,mts,cts,jsx,tsx}'],
+  },
+  resolve: {
+    alias: {
+      '@': resolve(__dirname, 'packages'),
+    },
+  },
+});