Adds the Offerings module and retargets the CI/CD pipeline to Api.SlpSoftware

Implements Unit 2 "Offerings" (backend module, admin CRUD UI with
drag-and-drop reordering, public GET /api/v1/offerings endpoint) and
executes the feature's D-15 CI/CD cutover, switching the deploy
pipeline's build/publish target from SlpModularCms.Api to
SlpModularCms.Api.SlpSoftware.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FWyStNL2ZsjrS7FLd7xvvN

frontend/src/i18n/locales/en/translation.json

@@ -10,6 +10,7 @@
         "dashboard": "Dashboard",
         "users": "Users",
         "cms": "CMS",
+        "offerings": "Offerings",
         "profile": "Profile",
         "settings": "Settings",
         "openMenu": "Open navigation",
@@ -230,6 +231,50 @@
             "successUnreachableToast": "Status saved — cliënt unreachable"
         }
     },
+    "offerings": {
+        "title": "Offerings",
+        "addButton": "Add Offering",
+        "emptyState": {
+            "heading": "No offerings yet",
+            "description": "Add your first offering to get started."
+        },
+        "table": {
+            "title": "Title",
+            "price": "Price",
+            "featured": "Featured",
+            "actions": "Actions"
+        },
+        "actions": {
+            "drag": "Drag to reorder",
+            "edit": "Edit",
+            "delete": "Delete",
+            "moveUp": "Move up",
+            "moveDown": "Move down",
+            "markFeatured": "Mark as featured",
+            "unmarkFeatured": "Remove featured"
+        },
+        "deleteDialog": {
+            "title": "Delete offering",
+            "message": "Are you sure you want to delete '{{title}}'?",
+            "confirmButton": "Delete",
+            "cancelButton": "Cancel"
+        },
+        "form": {
+            "createTitle": "New Offering",
+            "editTitle": "Edit Offering",
+            "titleLabel": "Title",
+            "descriptionLabel": "Description",
+            "priceLabel": "Price",
+            "priceNoteLabel": "Price note",
+            "featuresLabel": "Features",
+            "addFeatureButton": "Add feature",
+            "removeFeatureButton": "Remove",
+            "ctaLabelLabel": "Button text",
+            "featuredLabel": "Featured",
+            "submitButton": "Save",
+            "successToast": "Offering saved successfully"
+        }
+    },
     "error": {
         "403": {
             "title": "Access Denied",