Fix addedLabel activity deleted on same-board card move (#3907)

updateActivities() runs in a Cards.before.update hook and removed all
addedLabel activities for a card whenever 'boardId' appeared in the changed
fields. But Card.move() always re-sets boardId (even for a move within the same
board), so every card move deleted the card's label-added history.

Gate the removal/remap on an actual board change by comparing the pre-update
doc.boardId with modifier.$set.boardId. Cross-board moves still clean up / remap
the now-invalid addedLabel activities; same-board moves leave them intact.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

models/cards.js

@@ -3046,7 +3046,17 @@ Cards.helpers({
 //FUNCTIONS FOR creation of Activities
 
 async function updateActivities(doc, fieldNames, modifier) {
-  if (fieldNames.includes('labelIds') && fieldNames.includes('boardId')) {
+  // Only react to a real board CHANGE. This is a before.update hook, so doc is
+  // the pre-update card and modifier.$set.boardId is the new value. Card.move()
+  // always re-sets boardId (even for a move within the same board), so checking
+  // only fieldNames.includes('boardId') wrongly deleted the card's addedLabel
+  // activities on every move. See https://github.com/wekan/wekan/issues/3907
+  const boardIdChanged =
+    fieldNames.includes('boardId') &&
+    !!modifier.$set &&
+    modifier.$set.boardId !== doc.boardId;
+
+  if (fieldNames.includes('labelIds') && boardIdChanged) {
     const activities = await ReactiveCache.getActivities({
       activityType: 'addedLabel',
       cardId: doc._id,
@@ -3064,7 +3074,7 @@ async function updateActivities(doc, fieldNames, modifier) {
         await Activities.removeAsync(a._id);
       }
     }
-  } else if (fieldNames.includes('boardId')) {
+  } else if (boardIdChanged) {
     await Activities.removeAsync({
       activityType: 'addedLabel',
       cardId: doc._id,