- rename StatemRef/StatemCallError/StatemSendError -> GenStatem*
- move the inline unit test out of src; consolidate the Switch coverage
onto a single macro-driven harness in tests/gen_statem.rs
- drop the redundant hand-written Switch test machine and the two
untracked rejected-direction probes (succ_enums, typed_edges)
- rename examples statem_{fused,macro}.rs -> gen_statem_{fused,macro}.rs
- strip RFC/chunk/spike provenance and fix the mislabeled "throwaway"
example header and dead cross-references