Allow setting task due dates beyond the current day

Remove the date restriction in the task form to enable selecting any due date.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: cc2d271b-82f0-4d6a-9302-a0b067ffb429
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/1957c339-2757-4d1f-8e92-e9f71a1ce58e/cc2d271b-82f0-4d6a-9302-a0b067ffb429/CDwGDqK

client/src/components/tasks/TaskForm.tsx

@@ -194,7 +194,7 @@ export default function TaskForm({ task, onClose }: TaskFormProps) {
         priority: data.priority,
         status: data.status,
         assignedTo: data.assignedTo,
-        dueDate: data.dueDate?.toISOString(),
+        dueDate: data.dueDate || null,
       };
       updateMutation.mutate(submitData);
     } else {
@@ -405,9 +405,6 @@ export default function TaskForm({ task, onClose }: TaskFormProps) {
                     mode="single"
                     selected={field.value}
                     onSelect={field.onChange}
-                    disabled={(date) =>
-                      date < new Date(new Date().setHours(0, 0, 0, 0))
-                    }
                     initialFocus
                     locale={fr}
                   />