Ship Print Forge shop site (colors, photos, 3D viewer) (#2)

## Summary

- Rebrand the Django client template as Print Forge (`client_site` → `print_forge`) with shop + shipping enabled.
- Product listings support multiple photos, color variants (shared price/description/STL, per-color stock and photos), and a photo-first / 3D-second gallery.
- Public pages use 3D printer / printed-toy photography instead of leftover t-shirt mockups; beta CI deploys on `master`.

Closes #1
Infra: [server-infra#27](ai_ml_operations/server-infra#27) (easy deploy beta).

## Test plan

- [ ] Product page shows photo first, 3D model second; color swatches swap photos and stock
- [ ] Portal can upload multiple photos and per-color qty/images; STL stays shared
- [ ] Public home/about/gallery have no t-shirt mockups
- [ ] `manage.py test` passes
- [ ] After server-infra#27: beta deploy to `print-forge-preview.aimloperations.com`

Reviewed-on: #2

site/shipping/hooks.py

@@ -0,0 +1,31 @@
+from core.registry import (
+    register_dashboard_collector,
+    register_feature,
+    register_portal_nav,
+)
+
+
+def register() -> None:
+    register_feature("shipping")
+    register_portal_nav(
+        section="shipping",
+        label="Shipping",
+        url_name="shipping:shipment_list",
+        group="Retail",
+        order=50,
+    )
+    register_dashboard_collector(_dashboard)
+
+
+def _dashboard(request) -> dict:
+    from shipping.models import Shipment
+    from shop.models import Order
+
+    labeled = Shipment.objects.filter(status=Shipment.Status.LABELED).values_list(
+        "order_id", flat=True
+    )
+    return {
+        "unshipped_orders": Order.objects.filter(status=Order.Status.PAID)
+        .exclude(pk__in=labeled)
+        .count()
+    }