Fix working set IDs to match display order

BREAKING CHANGE: BuildWorkingSet() now accepts []*Task instead of *Filter

Problem:
- Working set IDs were assigned based on database query order (unsorted)
- Reports displayed tasks in sorted order (by urgency)
- Result: IDs didn't match displayed task positions (ID 1 wasn't first task)

Solution:
- Changed BuildWorkingSet() to accept pre-sorted task slice
- Reports now pass sorted tasks to BuildWorkingSet()
- IDs are assigned sequentially to match display order (1, 2, 3...)

Behavior:
- Reports rebuild working set on every execution with fresh IDs
- Task operations (done, modify, info) use saved working set IDs
- After completing a task, re-running report renumbers remaining tasks

Example:
  Before:  opal list shows ID 1 = low urgency task (wrong)
  After:   opal list shows ID 1 = highest urgency task (correct)

Tested scenarios:
✓ List report: IDs 1-N match urgency order
✓ Next report: IDs 1-5 match top urgent tasks
✓ Task completion: IDs renumber correctly after removal
✓ Multiple operations: Use saved working set (correct behavior)
✓ Different reports: Each builds own sequential IDs

opal-task/internal/engine/ws_test.go

@@ -10,8 +10,13 @@ func TestBuildWorkingSet(t *testing.T) {
 	task2, _ := CreateTask("Task 2")
 	task3, _ := CreateTask("Task 3")
 
-	// Build working set with default filter
-	ws, err := BuildWorkingSet(DefaultFilter())
+	// Get tasks and build working set
+	tasks, err := GetTasks(DefaultFilter())
+	if err != nil {
+		t.Fatalf("Failed to get tasks: %v", err)
+	}
+
+	ws, err := BuildWorkingSet(tasks)
 	if err != nil {
 		t.Fatalf("Failed to build working set: %v", err)
 	}
@@ -52,7 +57,12 @@ func TestLoadWorkingSet(t *testing.T) {
 	CreateTask("Load test 1")
 	CreateTask("Load test 2")
 
-	ws1, err := BuildWorkingSet(DefaultFilter())
+	tasks, err := GetTasks(DefaultFilter())
+	if err != nil {
+		t.Fatalf("Failed to get tasks: %v", err)
+	}
+
+	ws1, err := BuildWorkingSet(tasks)
 	if err != nil {
 		t.Fatalf("Failed to build working set: %v", err)
 	}
@@ -82,7 +92,12 @@ func TestWorkingSetWithFilter(t *testing.T) {
 
 	// Build working set with high priority filter
 	filter, _ := ParseFilter([]string{"priority:H"})
-	ws, err := BuildWorkingSet(filter)
+	tasks, err := GetTasks(filter)
+	if err != nil {
+		t.Fatalf("Failed to get tasks: %v", err)
+	}
+
+	ws, err := BuildWorkingSet(tasks)
 	if err != nil {
 		t.Fatalf("Failed to build filtered working set: %v", err)
 	}
@@ -105,7 +120,8 @@ func TestGetTaskByDisplayID(t *testing.T) {
 	CreateTask("Display ID test 2")
 	CreateTask("Display ID test 3")
 
-	ws, _ := BuildWorkingSet(DefaultFilter())
+	tasks, _ := GetTasks(DefaultFilter())
+	ws, _ := BuildWorkingSet(tasks)
 
 	// Test valid display IDs
 	for i := 1; i <= ws.Size(); i++ {
@@ -130,7 +146,8 @@ func TestWorkingSetGetTasks(t *testing.T) {
 	CreateTask("GetTasks test 1")
 	CreateTask("GetTasks test 2")
 
-	ws, _ := BuildWorkingSet(DefaultFilter())
+	taskList, _ := GetTasks(DefaultFilter())
+	ws, _ := BuildWorkingSet(taskList)
 
 	tasks := ws.GetTasks()
 	if len(tasks) != ws.Size() {