fix: improve priority handling based on feedback

- Fix TaskEditModal falsy check for task_order === 0 (use nullish check)
- Remove local optimistic state from TaskCard (derive directly from task.task_order)
- TaskCard now relies on TanStack Query optimistic updates from useUpdateTask mutation

Priority changes now use proper optimistic update pattern:
- onMutate: cancels queries, snapshots data, updates cache immediately
- onError: rolls back cache, shows error toast
- onSettled: ensures consistency with backend

This eliminates the dual state management and ensures consistent behavior.

archon-ui-main/src/features/projects/tasks/components/TaskCard.tsx

@@ -1,10 +1,10 @@
 import { Tag } from "lucide-react";
 import type React from "react";
-import { useCallback, useEffect, useState } from "react";
+import { useCallback } from "react";
 import { useDrag, useDrop } from "react-dnd";
 import { useTaskActions } from "../hooks";
 import type { Assignee, Task } from "../types";
-import { getTaskPriorityFromTaskOrder, TASK_PRIORITY_OPTIONS } from "../types/priority";
+import { getTaskPriorityFromTaskOrder } from "../types/priority";
 import { getOrderColor, getOrderGlow, ItemTypes } from "../utils/task-styles";
 import { TaskAssignee } from "./TaskAssignee";
 import { TaskCardActions } from "./TaskCardActions";
@@ -35,16 +35,8 @@ export const TaskCard: React.FC<TaskCardProps> = ({
   selectedTasks,
   onTaskSelect,
 }) => {
-  // Derive priority from task_order (backend field) instead of separate priority field
-  const [localPriority, setLocalPriority] = useState<Priority>(() => 
-    getTaskPriorityFromTaskOrder(task.task_order)
-  );
-
-  // Sync local priority when task_order changes
-  useEffect(() => {
-    const priorityFromTaskOrder = getTaskPriorityFromTaskOrder(task.task_order);
-    setLocalPriority(priorityFromTaskOrder);
-  }, [task.task_order]);
+  // Derive priority directly from task_order (backend field)
+  const currentPriority = getTaskPriorityFromTaskOrder(task.task_order);
 
   // Use business logic hook
   const { changeAssignee, changePriority, isUpdating } = useTaskActions(projectId);
@@ -68,10 +60,8 @@ export const TaskCard: React.FC<TaskCardProps> = ({
   }, [onDelete, task]);
 
   const handlePriorityChange = useCallback((priority: Priority) => {
-    // Update backend via task_order (conversion handled in hook)
+    // Update backend via task_order (optimistic updates handled in hook)
     changePriority(task.id, priority);
-    // Also update local state for immediate UI feedback
-    setLocalPriority(priority);
   }, [changePriority, task.id]);
 
   const handleAssigneeChange = useCallback(
@@ -229,7 +219,7 @@ export const TaskCard: React.FC<TaskCardProps> = ({
             <TaskAssignee assignee={task.assignee} onAssigneeChange={handleAssigneeChange} isLoading={isUpdating} />
 
             {/* Priority display with backend sync */}
-            <TaskPriority priority={localPriority} onPriorityChange={handlePriorityChange} isLoading={isUpdating} />
+            <TaskPriority priority={currentPriority} onPriorityChange={handlePriorityChange} isLoading={isUpdating} />
           </div>
         </div>
       </div>

archon-ui-main/src/features/projects/tasks/components/TaskEditModal.tsx

@@ -134,11 +134,12 @@ export const TaskEditModal = memo(
               <FormField>
                 <Label>Priority</Label>
                 <Select
-                  value={
-                    localTask?.task_order 
-                      ? getTaskPriorityFromTaskOrder(localTask.task_order)
-                      : "medium"
-                  }
+                  value={(() => {
+                    const order = localTask?.task_order;
+                    return order !== undefined 
+                      ? getTaskPriorityFromTaskOrder(order) 
+                      : "medium";
+                  })()}
                   onValueChange={(value) => {
                     // Convert priority to task_order value
                     const priorityOption = TASK_PRIORITY_OPTIONS.find(

archon-ui-main/src/features/projects/tasks/hooks/useTaskActions.ts

@@ -22,7 +22,7 @@ export const useTaskActions = (projectId: string): UseTaskActionsReturn => {
     [updateTaskMutation],
   );
 
-  // Priority change handler - maps priority to task_order
+  // Priority change handler - maps priority to task_order with optimistic updates
   const changePriority = useCallback(
     (taskId: string, newPriority: TaskPriority) => {
       // Convert priority to task_order value for backend