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

scripts/cms-logo-client.js

@@ -278,3 +278,38 @@ async function saveEditedLogo() {
     saveBtn.textContent = '💾 Szerkesztett logó mentése';
   }, 'image/png');
 }
+
+async function uploadPartner() {
+  const name = document.getElementById('partner-name').value.trim();
+  const file = document.getElementById('file-partner').files[0];
+  const msg = document.getElementById('msg-partner');
+  const pathOut = document.getElementById('path-partner');
+  const btn = document.getElementById('btn-partner');
+  pathOut.textContent = '';
+  if (!name) { msg.textContent = '❌ Adj meg egy fájlnevet.'; msg.className = 'msg err'; return; }
+  if (!file) { msg.textContent = '❌ Válassz PNG fájlt.'; msg.className = 'msg err'; return; }
+  if (file.type !== 'image/png') { msg.textContent = '❌ Csak PNG tölthető fel.'; msg.className = 'msg err'; return; }
+  btn.disabled = true;
+  try {
+    const bytes = new Uint8Array(await file.arrayBuffer());
+    const res = await fetch('/partner-logo?name=' + encodeURIComponent(name), {
+      method: 'POST',
+      headers: { 'Content-Type': 'image/png', 'X-CSRF-Token': CSRF_TOKEN },
+      body: bytes
+    });
+    if (res.status === 401) { location.href = '/login'; return; }
+    const json = await res.json();
+    if (json.ok) {
+      msg.textContent = '✅ Feltöltve.';
+      msg.className = 'msg ok';
+      pathOut.textContent = 'Elérési út: ' + json.path;
+    } else {
+      msg.textContent = '❌ ' + json.error;
+      msg.className = 'msg err';
+    }
+  } catch (e) {
+    msg.textContent = '❌ Hálózati hiba';
+    msg.className = 'msg err';
+  }
+  btn.disabled = false;
+}