Fix PPR empty generateStaticParams error and update dependencies

- Add placeholder fallback to generateStaticParams for cacheComponents compatibility
- Update npm packages within semver range (next 16.1.6, react 19.2.4, shiki 3.22.0, etc.)
- Add /new-post skill for blog publishing workflow
- Update CLAUDE.md with git remote mirroring docs

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

app/blog/[slug]/page.tsx

@@ -15,9 +15,10 @@ import { FooterCue } from '@/components/footer-cue';
 import { JsonLd } from '@/components/json-ld';
 
 export function generateStaticParams() {
-  return allPosts.map((post) => ({
+  const params = allPosts.map((post) => ({
     slug: post.slug || post.flattenedPath
   }));
+  return params.length > 0 ? params : [{ slug: '__placeholder__' }];
 }
 
 interface Props {