Add three-axis milling with independent CAM and Fusion validation (#1682)

Thanks @CypherNaught-0x.

crates/io/src/lib.rs

@@ -6,6 +6,7 @@
 #![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]
 #![forbid(unsafe_code)]
 
+pub mod cam;
 pub mod catalog;
 mod design;
 mod design_metadata;