The first compile this branch ever had. `cargo fmt` reflowed four files
and clippy passed at -D warnings untouched, but one test panicked:
`the_signature_does_not_change_with_scale`, on "attempt to multiply with
overflow".
It is the fixture, not the feature. `scene()`'s little LCG multiplied the
block's y by the golden-ratio constant with a plain `*` while the term
beside it already used `wrapping_mul`, so any scene taller than about 104
pixels overflowed in debug. Only the scale test builds one that large,
which is why 345 of 346 passed around it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>