Sort completed main tasks to the bottom of the list

Add asc(tasks.completed) as the primary sort key in getOrderClauses()
so completed tasks always appear after active ones regardless of the
chosen sort mode (position, priority, dueDate, title, createdAt).

Also apply the same completed-first ordering to:
- getSubtasks() in tasks.ts
- noDateTasks query in widgetSync.ts
- subtasks query in widgetSync.ts

Ref: simpl-liste#15

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

src/db/repository/tasks.ts

@@ -85,18 +85,19 @@ export async function getTasksByList(listId: string, filters?: TaskFilters) {
 
 function getOrderClauses(sortBy: SortBy, sortOrder: SortOrder) {
   const dir = sortOrder === 'asc' ? asc : desc;
+  // Always sort completed tasks to the bottom, then apply the requested sort
   switch (sortBy) {
     case 'priority':
-      return [dir(tasks.priority), asc(tasks.position)];
+      return [asc(tasks.completed), dir(tasks.priority), asc(tasks.position)];
     case 'dueDate':
-      return [dir(tasks.dueDate), asc(tasks.position)];
+      return [asc(tasks.completed), dir(tasks.dueDate), asc(tasks.position)];
     case 'title':
-      return [dir(tasks.title)];
+      return [asc(tasks.completed), dir(tasks.title)];
     case 'createdAt':
-      return [dir(tasks.createdAt)];
+      return [asc(tasks.completed), dir(tasks.createdAt)];
     case 'position':
     default:
-      return [asc(tasks.position), desc(tasks.createdAt)];
+      return [asc(tasks.completed), asc(tasks.position), desc(tasks.createdAt)];
   }
 }
 
@@ -105,7 +106,7 @@ export async function getSubtasks(parentId: string) {
     .select()
     .from(tasks)
     .where(eq(tasks.parentId, parentId))
-    .orderBy(asc(tasks.position));
+    .orderBy(asc(tasks.completed), asc(tasks.position));
 }
 
 export async function getTaskById(id: string) {

src/services/widgetSync.ts

@@ -89,7 +89,7 @@ export async function syncWidgetData(): Promise<void> {
           isNull(tasks.dueDate)
         )
       )
-      .orderBy(asc(tasks.position));
+      .orderBy(asc(tasks.completed), asc(tasks.position));
 
     const toWidgetTask = (t: typeof upcomingTasks[number]): WidgetTask => ({
       id: t.id,
@@ -117,7 +117,7 @@ export async function syncWidgetData(): Promise<void> {
           .select({ id: tasks.id, title: tasks.title, completed: tasks.completed })
           .from(tasks)
           .where(eq(tasks.parentId, task.id))
-          .orderBy(asc(tasks.position));
+          .orderBy(asc(tasks.completed), asc(tasks.position));
         task.subtasks = subs;
       }
     }