CI's `cargo fmt --all -- --check` has failed on every run because the
repo had no rustfmt config and was never formatted. Use the same settings
as EffectCraft/FilmCraft (max_width 160, use_small_heuristics Max), which
also keeps the churn small. Formatting only; no code changes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The Paint Bucket tool only filled the foreground colour; Photoshop's Fill
dropdown also offers Pattern. paint.bucket now takes contents="pattern"
(+ pattern/scale/angle), flood-filling the matched region with the pattern.
algo gains bucket_fill_src (fill colour from a per-pixel source closure);
bucket_fill delegates to it. pattern_cmds resolve_param/placement are now
pub(crate) for reuse. New bucket_fills_with_a_pattern test; clippy + wasm green.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
