raster: Integer Underflow in crop() Offset Handling Causes Capacity-Overflow Panic

The raster Rust crate's crop() function (src/editor.rs) clamps the crop width/height against source dimensions but only clamps the offset_x/offset_y parameters against 0, never against the source width/height. When an offset exceeds the corresponding source dimension, `width2 - offset_x` (or the height equivalent) underflows to a negative i32, which release builds do not trap; the negative value is then cast to usize inside Image::blank()'s Vec::with_capacity() call, triggering a capacity-overflow panic and crashing the process on a single crafted crop request.