feat(admin): authorize batch purchase starts

admin/internal/tasks/store.go

@@ -13,21 +13,27 @@ const sqliteWriteTimeout = 2 * time.Second
 type Store interface {
 	CreateDraft(context.Context, Draft) (Draft, error)
 	ListDrafts(context.Context) ([]Draft, error)
+	ListTasks(context.Context, TaskFilter) ([]TaskRow, error)
+	StartPurchases(context.Context, StartCommand, string) (StartResult, error)
 }
 type SQLiteStore struct {
-	database   *sql.DB
-	now        func() time.Time
-	createGate chan struct{}
+	database  *sql.DB
+	now       func() time.Time
+	writeGate chan struct{}
+	policy    StartPolicy
 }
 
 func NewSQLiteStore(database *sql.DB) (*SQLiteStore, error) {
 	if database == nil {
 		return nil, errors.New("database is required")
 	}
-	if _, err := database.Exec("SELECT 1 FROM tasks LIMIT 1"); err != nil {
+	if _, err := database.Exec("SELECT task_version, start_key, total_price_cap FROM order_authorizations LIMIT 1"); err != nil {
 		return nil, fmt.Errorf("tasks migration is not available: %w", err)
 	}
-	return &SQLiteStore{database: database, now: time.Now, createGate: make(chan struct{}, 1)}, nil
+	if _, err := database.Exec("SELECT 1 FROM purchase_attempts LIMIT 1"); err != nil {
+		return nil, fmt.Errorf("single-pass migration is not available: %w", err)
+	}
+	return &SQLiteStore{database: database, now: time.Now, writeGate: make(chan struct{}, 1)}, nil
 }
 
 func (store *SQLiteStore) CreateDraft(ctx context.Context, draft Draft) (Draft, error) {
@@ -36,8 +42,8 @@ func (store *SQLiteStore) CreateDraft(ctx context.Context, draft Draft) (Draft,
 	// SQLite permits one writer at a time. Serializing this store's short create
 	// transaction prevents concurrent retries of one create key from surfacing as busy.
 	select {
-	case store.createGate <- struct{}{}:
-		defer func() { <-store.createGate }()
+	case store.writeGate <- struct{}{}:
+		defer func() { <-store.writeGate }()
 	case <-writeContext.Done():
 		return Draft{}, writeContext.Err()
 	}