Migrate to Vite+ (vite-plus) unified toolchain

Replace Vite/Vitest with vite-plus, update WASM loading to native Vite 8
?init pattern, switch React compiler to @rolldown/plugin-babel, and
migrate git hooks from husky to vite-hooks.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

plugins/template-function-timestamp/tests/formatDatetime.test.ts

@@ -1,5 +1,5 @@
 import { tz } from '@date-fns/tz';
-import { describe, expect, it } from 'vitest';
+import { describe, expect, it } from 'vite-plus/test';
 import { calculateDatetime, formatDatetime } from '../src';
 
 describe('formatDatetime', () => {