# Map OpenAI-style dimensions to provider-specific params.
#   Gemini: aspect ratio (1:1, 16:9, 9:16) — no size param
#   Zhipu: fixed 1280x1280 — we map all our sizes to this
def size_for_provider [size: string, provider: string] {
    match $provider {
        "zhipu" => "1280x1280",
        _        => $size,
    }
}