chore(frontend): real ESLint instead of a placeholder; fix hook order (FLAW-19)

eslint.config.js with the recommended JS/TypeScript rules and the React
hooks rules; npm run lint runs ESLint and is part of the image build.
Errors fail the build, the 24 exhaustive-deps findings stay warnings.

It found two real bugs: TaskDetailModal and ManageColumnsModal called
their hooks after 'if (!isOpen) return null', so the hook count changed
whenever the dialog opened or closed. Both are now a thin wrapper plus a
content component. Also removes unused imports and dead code (old task
list share handlers, an unused realtime status, an unused rollup).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/features/triage/ManageColumnsModal.tsx

@@ -8,7 +8,6 @@ import {
   RotateCcw,
   Check,
   Columns,
-  Layers,
 } from 'lucide-react';
 import { KanbanColumn } from '../../lib/types';
 import { triggerHaptic } from '../../lib/api';
@@ -28,15 +27,17 @@ export const DEFAULT_KANBAN_COLUMNS: KanbanColumn[] = [
   { id: 'done', name: 'Erledigt', isDone: true, color: 'emerald' },
 ];
 
-export const ManageColumnsModal: React.FC<ManageColumnsModalProps> = ({
+// Wrapper and content split so the hooks always run in the same number (see TaskDetailModal)
+export const ManageColumnsModal: React.FC<ManageColumnsModalProps> = (props) =>
+  props.isOpen ? <ManageColumnsModalContent {...props} /> : null;
+
+const ManageColumnsModalContent: React.FC<ManageColumnsModalProps> = ({
   isOpen,
   onClose,
   initialColumns,
   onSave,
   listTitle,
 }) => {
-  if (!isOpen) return null;
-
   const [columns, setColumns] = useState<KanbanColumn[]>(() => {
     return initialColumns && initialColumns.length > 0 ? initialColumns : DEFAULT_KANBAN_COLUMNS;
   });

frontend/src/features/triage/TaskDetailModal.tsx

@@ -7,19 +7,16 @@ import {
   FileText,
   Plus,
   CheckSquare,
-  Clock,
-  Layers,
   Hash,
   AlertTriangle,
   Flame,
-  ChevronRight,
   Folder,
   Webhook,
   Lock,
   UserPlus,
   Repeat,
 } from 'lucide-react';
-import { Thought, SubTask, TaskList, TaskListMember, KanbanColumn, User, Recurrence } from '../../lib/types';
+import { Thought, TaskList, TaskListMember, KanbanColumn, User, Recurrence } from '../../lib/types';
 import { UserAvatar } from '../../components/UserAvatar';
 import { UserAutocomplete } from '../UserAutocomplete';
 import { triggerHaptic } from '../../lib/api';
@@ -51,9 +48,13 @@ interface TaskDetailModalProps {
   readOnly?: boolean; // Task belongs to a list shared with "viewer" permission
 }
 
-export const TaskDetailModal: React.FC<TaskDetailModalProps> = ({
+// The wrapper decides whether the dialog is shown; the content holds all hooks, so their number never
+// changes between renders (hooks after an early return break React when isOpen flips)
+export const TaskDetailModal: React.FC<TaskDetailModalProps> = (props) =>
+  props.isOpen && props.task ? <TaskDetailModalContent {...props} task={props.task} /> : null;
+
+const TaskDetailModalContent: React.FC<TaskDetailModalProps & { task: Thought }> = ({
   task,
-  isOpen,
   onClose,
   activeColumns,
   taskLists,
@@ -75,8 +76,6 @@ export const TaskDetailModal: React.FC<TaskDetailModalProps> = ({
   onDeleteTask,
   readOnly = false,
 }) => {
-  if (!isOpen || !task) return null;
-
   const [titleDraft, setTitleDraft] = useState(task.content);
   const [isEditingTitle, setIsEditingTitle] = useState(false);
 
@@ -144,7 +143,7 @@ export const TaskDetailModal: React.FC<TaskDetailModalProps> = ({
 
   const handleAddTagSubmit = async (e: React.FormEvent) => {
     e.preventDefault();
-    let cleaned = newTagDraft.trim().replace(/^#+/, '').toLowerCase();
+    const cleaned = newTagDraft.trim().replace(/^#+/, '').toLowerCase();
     if (!cleaned) return;
     const currentTags = Array.isArray(task.tags) ? [...task.tags] : [];
     if (!currentTags.includes(cleaned)) {
@@ -177,11 +176,6 @@ export const TaskDetailModal: React.FC<TaskDetailModalProps> = ({
     onUpdateDueDate(task, joinDue(addDays(daysOffset), splitDue(task.dueDate).time));
   };
 
-  const currentColumn = activeColumns.find((c) => c.id === task.kanbanStatus) ||
-    (task.isCompleted
-      ? activeColumns.find((c) => c.isDone) || activeColumns[activeColumns.length - 1]
-      : activeColumns.find((c) => !c.isDone) || activeColumns[0]);
-
   const subtasks = Array.isArray(task.subtasks) ? task.subtasks : [];
   const completedSubtasks = subtasks.filter((s) => s.isCompleted).length;
   const subtasksPercent = subtasks.length > 0 ? Math.round((completedSubtasks / subtasks.length) * 100) : 0;

frontend/src/features/triage/TasksView.tsx

@@ -15,19 +15,18 @@ import {
   Layers,
   Users,
   CheckSquare,
-  User as UserIcon,
+  User as 
   Lock,
   Hash,
   AlertTriangle,
   Flame,
   Settings,
-  ChevronDown,
   Folder,
   Filter,
   Webhook,
   Repeat,
 } from 'lucide-react';
-import { TaskList, Thought, SubTask, Team, User, TaskListShare, TaskListMember, KanbanColumn, PriorityLevel, Recurrence, RECURRENCE_LABELS } from '../../lib/types';
+import { TaskList, Thought, SubTask, Team, User, TaskListMember, KanbanColumn, PriorityLevel, Recurrence, RECURRENCE_LABELS } from '../../lib/types';
 import { formatDue, isDueToday, isOverdue, localDay, splitDue } from '../../lib/due';
 import { api, triggerHaptic } from '../../lib/api';
 import { UnifiedShareModal } from '../../components/UnifiedShareModal';
@@ -92,10 +91,6 @@ export const TasksView: React.FC<TasksViewProps> = ({
   // Share TaskList modal state
   const [showShareListModal, setShowShareListModal] = useState(false);
   const [sharingTaskList, setSharingTaskList] = useState<TaskList | null>(null);
-  const [addShareType, setAddShareType] = useState<'team' | 'user'>('team');
-  const [selectedShareTargetId, setSelectedShareTargetId] = useState('');
-  const [selectedShareUser, setSelectedShareUser] = useState<User | null>(null);
-  const [shareLoading, setShareLoading] = useState(false);
 
   // Detail modal state
   const [detailTaskId, setDetailTaskId] = useState<string | null>(null);
@@ -854,8 +849,6 @@ export const TasksView: React.FC<TasksViewProps> = ({
 
   const handleOpenShareModal = async (tl: TaskList) => {
     setSharingTaskList(tl);
-    setSelectedShareTargetId('');
-    setSelectedShareUser(null);
     setShowShareListModal(true);
     try {
       const [freshTeams, freshUsers, freshShares] = await Promise.all([
@@ -871,60 +864,6 @@ export const TasksView: React.FC<TasksViewProps> = ({
     }
   };
 
-  const handleAddShare = async () => {
-    if (!sharingTaskList) return;
-    const targetId = addShareType === 'team' ? selectedShareTargetId : selectedShareUser?.id;
-    if (!targetId) return;
-    setShareLoading(true);
-    triggerHaptic(15);
-    try {
-      await api.addTaskListShare(sharingTaskList.id, {
-        targetType: addShareType,
-        targetId: targetId,
-      });
-      const [freshLists, freshShares] = await Promise.all([
-        api.getTaskLists(),
-        api.getTaskListShares(sharingTaskList.id).catch(() => []),
-      ]);
-      setTaskLists(freshLists);
-      const updated = freshLists.find((l) => l.id === sharingTaskList.id);
-      if (updated) {
-        setSharingTaskList({ ...updated, shares: freshShares });
-      }
-      setSelectedShareTargetId('');
-      setSelectedShareUser(null);
-      await loadData();
-    } catch (err: any) {
-      alert(err.message || 'Fehler beim Hinzufügen der Freigabe');
-    } finally {
-      setShareLoading(false);
-    }
-  };
-
-  const handleRemoveShare = async (shareId: string) => {
-    if (!sharingTaskList) return;
-    if (!window.confirm('Freigabe wirklich aufheben?')) return;
-    setShareLoading(true);
-    triggerHaptic(15);
-    try {
-      await api.removeTaskListShare(sharingTaskList.id, shareId);
-      const [freshLists, freshShares] = await Promise.all([
-        api.getTaskLists(),
-        api.getTaskListShares(sharingTaskList.id).catch(() => []),
-      ]);
-      setTaskLists(freshLists);
-      const updated = freshLists.find((l) => l.id === sharingTaskList.id);
-      if (updated) {
-        setSharingTaskList({ ...updated, shares: freshShares });
-      }
-      await loadData();
-    } catch (err: any) {
-      alert(err.message || 'Fehler beim Entfernen der Freigabe');
-    } finally {
-      setShareLoading(false);
-    }
-  };
-
   const handleSaveColumns = async (newColumns: KanbanColumn[]) => {
     triggerHaptic(15);
     if (currentSelectedList && selectedListId !== 'all') {