keyframe: never-crash deny lints (craftrules standards/never-crash.md)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
(cherry picked from commit 2232354b902238827b2e80a29ef266c2e5bde272)
(cherry picked from commit 95da7943454ca5b2575993d11f9ba046822ce255)

crates/keyframe/src/lib.rs

@@ -8,6 +8,8 @@
 //!   (pixels/second), evaluated through an arc-length table.
 //! * Auto-Bezier and continuous-Bezier keys derive their tangents from their neighbours.
 
+#![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]
+
 pub mod text_doc;
 pub mod value;