refactor: remove snippets feature and n8n project detection

- Remove snippets page, component, API route, Directus types, and setup script
- Remove snippets section from About.tsx (card, modal, state)
- Remove snippets link from 404 page, simplify layout
- Remove n8n Docker event and callback handler workflows (auto project detection)
- Remove Gitea runner setup and deploy scripts

app/api/snippets/route.ts

@@ -1,21 +0,0 @@
-import { NextRequest, NextResponse } from 'next/server';
-import { getSnippets } from '@/lib/directus';
-
-const CACHE_TTL = 300; // 5 minutes
-
-export async function GET(request: NextRequest) {
-  try {
-    const { searchParams } = new URL(request.url);
-    const limit = parseInt(searchParams.get('limit') || '10');
-    const featured = searchParams.get('featured') === 'true' ? true : undefined;
-    
-    const snippets = await getSnippets(limit, featured);
-    
-    return NextResponse.json(
-      { snippets: snippets || [] },
-      { headers: { 'Cache-Control': `public, s-maxage=${CACHE_TTL}, stale-while-revalidate=${CACHE_TTL * 2}` } }
-    );
-  } catch (_error) {
-    return NextResponse.json({ error: 'Failed to fetch snippets' }, { status: 500 });
-  }
-}