feat: bulk delete, team dispatch, calendar views, timeline colors

- Multi-select bulk delete in all 5 list views (Artefacts, Posts, Tasks,
  Issues, Assets) with cascade deletes and confirmation modals
- Team-based issue dispatch: team picker on public issue form, team filter
  on Issues page, copy public link from Team page and Issues header,
  team assignment in IssueDetailPanel
- Month/Week toggle on PostCalendar and TaskCalendarView
- Month/Week/Day zoom on project and campaign timelines (InteractiveTimeline)
  and ProjectDetail GanttView, with Month as default
- Custom timeline bar colors: clickable color dot with 12-color palette
  popover on project, campaign, and task timeline bars
- Artefacts default view changed to list
- BulkSelectBar reusable component
- i18n keys for all new features (en + ar)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/src/pages/Tasks.jsx

@@ -6,6 +6,8 @@ import { useLanguage } from '../i18n/LanguageContext'
 import { api, PRIORITY_CONFIG, getBrandColor } from '../utils/api'
 import TaskCard from '../components/TaskCard'
 import TaskDetailPanel from '../components/TaskDetailPanel'
+import BulkSelectBar from '../components/BulkSelectBar'
+import Modal from '../components/Modal'
 import TaskCalendarView from '../components/TaskCalendarView'
 import DatePresetPicker from '../components/DatePresetPicker'
 import EmptyState from '../components/EmptyState'
@@ -45,6 +47,8 @@ export default function Tasks() {
   const [filterOverdue, setFilterOverdue] = useState(false)
   const [activePreset, setActivePreset] = useState('')
   const [showFilters, setShowFilters] = useState(false)
+  const [selectedIds, setSelectedIds] = useState(new Set())
+  const [showBulkDeleteConfirm, setShowBulkDeleteConfirm] = useState(false)
 
   // Assignable users & team
   const [assignableUsers, setAssignableUsers] = useState([])
@@ -54,17 +58,17 @@ export default function Tasks() {
 
   useEffect(() => { loadTasks() }, [currentUser])
   useEffect(() => {
-    api.get('/users/assignable').then(res => setAssignableUsers(res.data || res || [])).catch(() => {})
-    api.get('/projects').then(res => setProjects(res.data || res || [])).catch(() => {})
+    api.get('/users/assignable').then(res => setAssignableUsers(Array.isArray(res) ? res : [])).catch(() => {})
+    api.get('/projects').then(res => setProjects(Array.isArray(res) ? res : [])).catch(() => {})
     if (isSuperadmin) {
-      api.get('/team').then(res => setUsers(res.data || res || [])).catch(() => {})
+      api.get('/team').then(res => setUsers(Array.isArray(res) ? res : [])).catch(() => {})
     }
   }, [isSuperadmin])
 
   const loadTasks = async () => {
     try {
       const res = await api.get('/tasks')
-      setTasks(res.data || res || [])
+      setTasks(Array.isArray(res) ? res : [])
     } catch (err) {
       console.error('Failed to load tasks:', err)
     } finally {
@@ -177,6 +181,33 @@ export default function Tasks() {
     }
   }
 
+  const handleBulkDelete = async () => {
+    try {
+      await api.post('/tasks/bulk-delete', { ids: [...selectedIds] })
+      toast.success(t('tasks.deleted'))
+      setSelectedIds(new Set())
+      setShowBulkDeleteConfirm(false)
+      loadTasks()
+    } catch (err) {
+      console.error('Bulk delete failed:', err)
+      toast.error(t('common.deleteFailed'))
+    }
+  }
+
+  const toggleSelect = (id) => {
+    setSelectedIds(prev => {
+      const next = new Set(prev)
+      if (next.has(id)) next.delete(id)
+      else next.add(id)
+      return next
+    })
+  }
+
+  const toggleSelectAll = () => {
+    if (selectedIds.size === sortedListTasks.length) setSelectedIds(new Set())
+    else setSelectedIds(new Set(sortedListTasks.map(t => t._id || t.id)))
+  }
+
   const handleMove = async (taskId, newStatus) => {
     try {
       await api.patch(`/tasks/${taskId}`, { status: newStatus })
@@ -594,10 +625,27 @@ export default function Tasks() {
 
           {/* ─── List View ───────────────────────── */}
           {viewMode === 'list' && (
+            <>
+              {selectedIds.size > 0 && (
+                <BulkSelectBar
+                  selectedCount={selectedIds.size}
+                  onClear={() => setSelectedIds(new Set())}
+                  onDelete={() => setShowBulkDeleteConfirm(true)}
+                />
+              )}
             <div className="bg-white rounded-xl border border-border overflow-hidden">
               <table className="w-full text-sm">
                 <thead>
                   <tr className="border-b border-border bg-surface-secondary/50">
+                    <th className="w-8 px-3 py-2.5">
+                      <input
+                        type="checkbox"
+                        checked={sortedListTasks.length > 0 && selectedIds.size === sortedListTasks.length}
+                        onChange={toggleSelectAll}
+                        className="w-3.5 h-3.5 rounded border-border text-brand-primary cursor-pointer"
+                        onClick={e => e.stopPropagation()}
+                      />
+                    </th>
                     <th className="w-8 px-3 py-2.5"></th>
                     <th
                       className="text-left px-3 py-2.5 text-xs font-semibold text-text-tertiary uppercase cursor-pointer hover:text-text-primary"
@@ -645,6 +693,14 @@ export default function Tasks() {
                         onClick={() => openTask(task)}
                         className="border-b border-border-light hover:bg-surface-secondary/30 cursor-pointer transition-colors group"
                       >
+                        <td className="px-3 py-2.5" onClick={e => e.stopPropagation()}>
+                          <input
+                            type="checkbox"
+                            checked={selectedIds.has(task._id || task.id)}
+                            onChange={() => toggleSelect(task._id || task.id)}
+                            className="w-3.5 h-3.5 rounded border-border text-brand-primary cursor-pointer"
+                          />
+                        </td>
                         <td className="px-3 py-2.5">
                           <div className={`w-2.5 h-2.5 rounded-full ${priority.color}`} title={priority.label} />
                         </td>
@@ -686,6 +742,7 @@ export default function Tasks() {
                 </tbody>
               </table>
             </div>
+            </>
           )}
 
           {/* ─── Calendar View ───────────────────── */}
@@ -695,6 +752,19 @@ export default function Tasks() {
         </>
       )}
 
+      {/* ─── Bulk Delete Confirmation Modal ─────── */}
+      <Modal
+        isOpen={showBulkDeleteConfirm}
+        onClose={() => setShowBulkDeleteConfirm(false)}
+        title={t('common.bulkDeleteConfirm').replace('{count}', selectedIds.size)}
+        isConfirm
+        danger
+        confirmText={t('common.deleteSelected')}
+        onConfirm={handleBulkDelete}
+      >
+        {t('common.bulkDeleteDesc')}
+      </Modal>
+
       {/* ─── Task Detail Side Panel ──────────────── */}
       {selectedTask && (
         <TaskDetailPanel