Fix push notifications and hide action button on completed tasks

- Add push_certs directory to Dockerfile for APNs support
- Fix notification_id conversion using strconv.FormatUint instead of string(rune())
- Remove "view" from completed tasks button_types so action button is hidden

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

internal/repositories/task_repo.go

@@ -233,7 +233,7 @@ func (r *TaskRepository) GetKanbanData(residenceID uint, daysThreshold int) (*mo
 		{
 			Name:        "completed_tasks",
 			DisplayName: "Completed",
-			ButtonTypes: []string{"view"},
+			ButtonTypes: []string{},
 			Icons:       map[string]string{"ios": "checkmark.circle", "android": "CheckCircle"},
 			Color:       "#34C759",
 			Tasks:       completed,
@@ -360,7 +360,7 @@ func (r *TaskRepository) GetKanbanDataForMultipleResidences(residenceIDs []uint,
 		{
 			Name:        "completed_tasks",
 			DisplayName: "Completed",
-			ButtonTypes: []string{"view"},
+			ButtonTypes: []string{},
 			Icons:       map[string]string{"ios": "checkmark.circle", "android": "CheckCircle"},
 			Color:       "#34C759",
 			Tasks:       completed,