Function ratatui_set_custom_font

#[no_mangle]
pub extern "C" fn ratatui_set_custom_font(
    handle: *mut c_void,
    font_data: *const u8,
    font_len: u32,
) -> u8

Replaces the embedded JetBrains Mono font with custom TTF bytes.

The cell width/height are recomputed from the new font’s metrics, and the glyph cache is dropped. The pixel buffer is not resized here; callers that rely on a specific pixel size should re-create the handle if the new font changes cell dimensions.

Returns

1 on success, 0 if handle is null, font_data is null/empty, or the bytes are not a valid font.