Update ReactiveCache call sites to use async/await for Meteor 3.0

Part 3 of ReactiveCache async migration:
- Add await before all ReactiveCache.getX() calls
- Make functions containing ReactiveCache calls async
- Convert forEach/map/filter loops with async callbacks to for...of
- Update model helpers, Meteor methods, JsonRoutes handlers
- Update collection hooks (.before/.after insert/update/remove)
- Update .allow() callbacks to async

Files updated across models/ and server/ directories:
- Model files: cards, boards, lists, swimlanes, activities, users,
  checklists, checklistItems, customFields, attachments, integrations,
  cardComments, settings files, creators, exporters, and more
- Server files: publications, methods, notifications, routes, migrations

server/migrations/migrateAttachments.js

@@ -14,7 +14,7 @@ if (Meteor.isServer) {
      * @param {string} attachmentId - The old attachment ID
      * @returns {Object} - Migration result
      */
-    migrateAttachment(attachmentId) {
+    async migrateAttachment(attachmentId) {
       if (!this.userId) {
         throw new Meteor.Error('not-authorized', 'Must be logged in');
       }
@@ -27,7 +27,7 @@ if (Meteor.isServer) {
         }
 
         // Check if already migrated
-        const existingAttachment = ReactiveCache.getAttachment(attachmentId);
+        const existingAttachment = await ReactiveCache.getAttachment(attachmentId);
         if (existingAttachment) {
           return { success: true, message: 'Already migrated', attachmentId };
         }
@@ -72,7 +72,7 @@ if (Meteor.isServer) {
      * @param {string} cardId - The card ID
      * @returns {Object} - Migration results
      */
-    migrateCardAttachments(cardId) {
+    async migrateCardAttachments(cardId) {
       if (!this.userId) {
         throw new Meteor.Error('not-authorized', 'Must be logged in');
       }
@@ -85,7 +85,7 @@ if (Meteor.isServer) {
 
       try {
         // Get all old attachments for this card
-        const oldAttachments = ReactiveCache.getAttachments({ 'meta.cardId': cardId });
+        const oldAttachments = await ReactiveCache.getAttachments({ 'meta.cardId': cardId });
 
         for (const attachment of oldAttachments) {
           const result = Meteor.call('migrateAttachment', attachment._id);
@@ -113,14 +113,14 @@ if (Meteor.isServer) {
      * @param {string} cardId - The card ID (optional)
      * @returns {Object} - Migration status
      */
-    getAttachmentMigrationStatus(cardId) {
+    async getAttachmentMigrationStatus(cardId) {
       if (!this.userId) {
         throw new Meteor.Error('not-authorized', 'Must be logged in');
       }
 
       try {
         const selector = cardId ? { 'meta.cardId': cardId } : {};
-        const allAttachments = ReactiveCache.getAttachments(selector);
+        const allAttachments = await ReactiveCache.getAttachments(selector);
 
         const status = {
           total: allAttachments.length,