feat(Navbar): wire anchor links to page sections

Werkzeuge→#werkzeuge, Blog→#blog, Über Björn→#ueber-bjoern.
Shop remains /shop (no matching section). Added matching id attributes
to Tools, Blog and About section root elements.

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

app/components/Blog.tsx

@@ -33,7 +33,7 @@ const secondary = [
 
 export function Blog() {
   return (
-    <div className="flex flex-col gap-[3rem] items-start pb-[4rem] w-full bg-[#f5f0e8]">
+    <div id="blog" className="flex flex-col gap-[3rem] items-start pb-[4rem] w-full bg-[#f5f0e8]">
 
       {/* Section header */}
       <div className="flex flex-col gap-[0.5rem] items-start px-[5rem] w-full">