// SPDX-FileCopyrightText: 2026 Andrei G <bug-ops>
// SPDX-License-Identifier: MIT OR Apache-2.0
/// Returns the effective database URL for the current build.
///
/// Prefers `database_url` when set and non-empty (postgres backend), otherwise falls
/// back to `sqlite_path` (sqlite backend). Mirrors the logic in `AppBuilder::build_memory`.
pub