feat: partners section on the homepage (logo + URL, CMS upload)

- home.json gains a partners block (title/subtitle/items: name, url, logo),
  rendered on the homepage under the services section (next/image logos
  linking out with rel=noopener)
- CMS: partner logos uploadable from the 🎨 Logó page via POST /partner-logo
  (PNG, 1 MiB cap, filename sanitized to a slug, written to public/partners/)
- schema + types extended; guide updated

Closes MITHOME-83

proto/src/app/page.tsx

@@ -1,4 +1,5 @@
 import { content } from '@/content'
+import Image from 'next/image'
 
 const { home: pageContent } = content.pages
 
@@ -210,6 +211,45 @@ export default function Home() {
         </div>
       </section>
 
+      {/* Partners Section */}
+      {pageContent.partners.items.length > 0 && (
+        <section className="py-16">
+          <div className="max-w-5xl mx-auto px-4 sm:px-6 lg:px-8">
+            <h2 className="text-3xl font-bold text-center mb-3" style={{ color: 'var(--color-foreground)' }}>
+              {pageContent.partners.title}
+            </h2>
+            <p className="text-center mb-10" style={{ color: 'var(--color-foreground-muted)' }}>
+              {pageContent.partners.subtitle}
+            </p>
+            <div className="flex flex-wrap justify-center items-center gap-10">
+              {pageContent.partners.items.map((partner) => (
+                <a
+                  key={partner.name}
+                  href={partner.url}
+                  target="_blank"
+                  rel="noopener noreferrer"
+                  className="group flex flex-col items-center gap-3 opacity-80 hover:opacity-100 transition-opacity duration-200"
+                  title={partner.name}
+                >
+                  <span className="relative h-12 w-40">
+                    <Image
+                      src={partner.logo}
+                      alt={partner.name}
+                      fill
+                      sizes="160px"
+                      className="object-contain"
+                    />
+                  </span>
+                  <span className="text-sm" style={{ color: 'var(--color-foreground-muted)' }}>
+                    {partner.name}
+                  </span>
+                </a>
+              ))}
+            </div>
+          </div>
+        </section>
+      )}
+
       {/* CTA Section */}
       <section 
         className="py-20 relative overflow-hidden"