Add about/contact/installments pages, fix category slot bugs, wire live branding

- Enlarge category carousel thumbnails (90px -> 104-140px responsive) and
  confirm the slider/categories/banner static-image slots are all reading
  correctly from the CMS (verified live, not a wiring bug)
- Fix installments page dropping "هندزفری و هدفون": it's a level-3 category,
  not level-2, so level2.find() silently missed it - use findNode() over the
  whole tree instead
- Extend gen-category-placeholders.mjs to generate a placeholder for every
  category at every level (was level-2 only), needed for the fix above
- Add /about, /contact, /installments pages
  - About: real copy transcribed from the live moalem.shop theme, real
    product photos from the API, text-only brand strip (no scraped logos)
  - Contact: ContactForm.tsx posts to the real POST /contact-submissions,
    branch cards with key-less Google Maps embeds
  - Installments: flat brand-colored hero (no photo/gradient), category
    highlights reusing the same categories slot images as the homepage
- Replace the placeholder header/footer phone number with the real one, add
  real branch addresses and Instagram/Telegram links (src/data/site.ts),
  pulled from the live theme's footer
- Wire logo/favicon to GET /website/favicon (getFavicon() in api.ts) instead
  of the static bundled files, so a dashboard upload now shows automatically;
  layout.tsx metadata is now generateMetadata() to support this. The tenant's
  uploaded logo/favicon currently belongs to a different business - the
  wiring is correct and will self-correct once that's fixed in the dashboard

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/components/ContactForm.tsx

@@ -0,0 +1,88 @@
+"use client";
+
+import { useState } from "react";
+import { submitContactForm } from "@/lib/api";
+
+type Status = "idle" | "submitting" | "sent" | "error";
+
+// Posts straight to POST /tenants/moalem.shop/contact-submissions — a real,
+// documented endpoint, no bearer required.
+export default function ContactForm() {
+  const [status, setStatus] = useState<Status>("idle");
+
+  async function handleSubmit(e: React.FormEvent<HTMLFormElement>) {
+    e.preventDefault();
+    const form = new FormData(e.currentTarget);
+    const name = String(form.get("name") || "").trim();
+    const title = String(form.get("title") || "").trim();
+    const text = String(form.get("text") || "").trim();
+    const email = String(form.get("email") || "").trim();
+    const cellNumber = String(form.get("cellNumber") || "").trim();
+    if (!name || !title || !text) return;
+
+    setStatus("submitting");
+    try {
+      await submitContactForm({
+        name,
+        title,
+        text,
+        email: email || undefined,
+        cellNumber: cellNumber || undefined,
+      });
+      setStatus("sent");
+      e.currentTarget.reset();
+    } catch {
+      setStatus("error");
+    }
+  }
+
+  if (status === "sent") {
+    return (
+      <div className="flex flex-col items-center gap-3 rounded-2xl border border-line bg-surface p-10 text-center">
+        <p className="text-[15px] font-bold text-ink">پیام شما با موفقیت ارسال شد.</p>
+        <p className="text-[13px] text-body">همکاران ما در اسرع وقت با شما تماس می‌گیرند.</p>
+        <button
+          onClick={() => setStatus("idle")}
+          className="mt-2 rounded-lg border border-line px-4 py-2 text-[13px] text-ink-soft transition hover:border-brand hover:text-brand"
+        >
+          ارسال پیام دیگر
+        </button>
+      </div>
+    );
+  }
+
+  const input =
+    "h-12 w-full rounded-xl border border-line bg-white px-4 text-sm outline-none transition focus:border-brand";
+
+  return (
+    <form onSubmit={handleSubmit} className="space-y-4">
+      <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
+        <input name="name" required placeholder="نام و نام خانوادگی" className={input} />
+        <input name="cellNumber" placeholder="شماره موبایل" inputMode="tel" className={input} />
+      </div>
+      <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
+        <input name="email" type="email" placeholder="ایمیل (اختیاری)" className={input} />
+        <input name="title" required placeholder="موضوع پیام" className={input} />
+      </div>
+      <textarea
+        name="text"
+        required
+        rows={5}
+        placeholder="متن پیام شما…"
+        className="w-full rounded-xl border border-line bg-white p-4 text-sm outline-none transition focus:border-brand"
+      />
+
+      {status === "error" && (
+        <p className="text-[12.5px] text-brand">ارسال پیام ناموفق بود. لطفاً دوباره تلاش کنید.</p>
+      )}
+
+      <button
+        type="submit"
+        disabled={status === "submitting"}
+        className="flex h-12 w-full items-center justify-center rounded-xl bg-brand text-sm font-bold text-white transition hover:bg-brand-dark disabled:cursor-not-allowed disabled:opacity-50 sm:w-auto sm:px-10"
+      >
+        {status === "submitting" ? "در حال ارسال…" : "ارسال پیام"}
+      </button>
+    </form>
+  );
+}