Fix Vercel build failure: remove TS generics from inline script and pin Node version

The Vercel deployment failed with `Expected ":" but found ")"` because
esbuild on Vercel parsed TypeScript generic syntax
(`querySelectorAll<HTMLButtonElement>`) as JavaScript comparison operators
in the blog page inline `<script>` tag.

- Remove TypeScript generics from blog/index.astro inline script (not
  needed — code only uses `.dataset` and `.style` from base Element)
- Pin Node engine to >=22.12.0 to match Astro 6.x requirements and
  prevent Vercel from auto-selecting an incompatible version

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

src/pages/blog/index.astro

@@ -91,8 +91,8 @@ const categories = ['All Posts', ...BLOG_CATEGORIES];
 
 <script>
   document.addEventListener('DOMContentLoaded', () => {
-    const buttons = document.querySelectorAll<HTMLButtonElement>('.blog-filter-btn');
-    const posts = document.querySelectorAll<HTMLElement>('.blog-post-card');
+    const buttons = document.querySelectorAll('.blog-filter-btn');
+    const posts = document.querySelectorAll('.blog-post-card');
     const emptyState = document.getElementById('blog-empty');
 
     buttons.forEach(btn => {