Function init_ro_pool 

pub async fn init_ro_pool(
    primary: &Db,
    _config: &DbConfig,
    kind: DbKind,
    resolved_url: &str,
) -> Result<Db, KipukaError>

Initialize a read-only connection pool for GET handlers.

For SQLite file-backed databases, this opens a ?mode=ro pool that never acquires the write lock, enabling concurrent reads during writes (WAL concurrency benefit). For :memory: and non-SQLite backends, returns a clone of the primary pool.