feat(admin): implement unified submission and newsletter management

Introduce a centralized system to manage all website form submissions and newsletter subscriptions.
- Add `Submission` and `NewsletterSubscription` models with MongoDB schema validation
- Implement `submissionController` and `newsletterSubscriptionController` for CRUD operations and filtering
- Create a unified admin UI for reviewing submissions across different sources (home, request, contact, partnership, newsletter)
- Add database migration scripts for creating collections and indexes
- Refactor partnership inquiry forms to use a fixed field structure
- Update admin navigation and server CORS settings to support PATCH requests

views/admin/partnerships/index.ejs

@@ -55,11 +55,20 @@
 
 <%- include("partials/templates", { editorUi }) %>
 
+<script type="application/json" id="partnershipsPageBootstrapJson"><%- JSON.stringify({
+  data,
+  backendUrl,
+  editorConfig,
+  editorUi,
+}) %></script>
 <script>
-  window.partnershipsPageData = <%- JSON.stringify(data) %>;
-  window.partnershipsBackendUrl = <%- JSON.stringify(backendUrl) %>;
-  window.partnershipsEditorConfig = <%- JSON.stringify(editorConfig) %>;
-  window.partnershipsEditorUi = <%- JSON.stringify(editorUi) %>;
+  const partnershipsPageBootstrap = JSON.parse(
+    document.getElementById("partnershipsPageBootstrapJson").textContent || "{}",
+  );
+  window.partnershipsPageData = partnershipsPageBootstrap.data;
+  window.partnershipsBackendUrl = partnershipsPageBootstrap.backendUrl;
+  window.partnershipsEditorConfig = partnershipsPageBootstrap.editorConfig;
+  window.partnershipsEditorUi = partnershipsPageBootstrap.editorUi;
 </script>
 <%- include("partials/editor-script") %>