fix(activities): keep comment and postpone open for assignees under creator-only edit

Allow dueAt/description patches for collaborators when editPolicy is creator-only, and show the no-edit warning only when they try to change locked fields—not as a permanent banner.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/web/src/components/activities/ActivityQuickView.vue

@@ -29,7 +29,7 @@ import {
   startOfLocalDay,
 } from '@/lib/jalali';
 import { useAuthStore } from '@/stores/auth';
-import { canMutateActivity } from '@/lib/activity-access';
+import { canCollaborateOnActivity, canMutateActivity } from '@/lib/activity-access';
 import ActivityCommentSheet from '@/components/activities/ActivityCommentSheet.vue';
 import JalaliDateInput from '@/components/JalaliDateInput.vue';
 
@@ -202,6 +202,9 @@ const isClosed = computed(
   () => activity.value?.status === 'done' || activity.value?.status === 'canceled',
 );
 const canMutate = computed(() => canMutateActivity(activity.value, auth.user));
+const canCollaborate = computed(() =>
+  canCollaborateOnActivity(activity.value, auth.user),
+);
 const needsEveryone = computed(
   () => activity.value?.completionMode === 'all' && (activity.value.assignees?.length ?? 0) > 1,
 );
@@ -535,7 +538,7 @@ function openFull() {
             type="primary"
             shape="circle"
             aria-label="یادداشت جدید"
-            :disabled="!canMutate"
+            :disabled="!canCollaborate"
             @click="commentOpen = true"
           >
             <template #icon><PlusOutlined /></template>
@@ -642,14 +645,14 @@ function openFull() {
           <a-flex align="center" :gap="8">
             <a-select
               v-model:value="postponeKey"
-              :disabled="saving || loading || isClosed || !canMutate"
+              :disabled="saving || loading || isClosed || !canCollaborate"
               :options="postponeChoices.map((item) => ({ value: item.key, label: item.label }))"
               :dropdown-style="{ zIndex: 1200 }"
               style="flex: 1"
             />
             <a-button
               type="primary"
-              :disabled="saving || loading || isClosed || !canMutate || !postponeReady"
+              :disabled="saving || loading || isClosed || !canCollaborate || !postponeReady"
               @click="applyPostpone"
             >
               تعویق
@@ -660,7 +663,7 @@ function openFull() {
             v-model="customDue"
             mode="datetime"
             placeholder="تاریخ و ساعت"
-            :disabled="!canMutate"
+            :disabled="!canCollaborate"
           />
         </a-flex>