Replace the unwrap/expect calls in path closing, bounds, Pathfinder output
and gradient sampling with let-else / if-let; the ASE reader uses checked
offsets (a 32-bit length could overflow on wasm32). Both crates now deny
unwrap/expect/panic/unimplemented/todo/unreachable.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
