8c1c466b63
Now that the optimizer TailCall/inline bug is fixed, SM/REM, FM/MOD, */, and */MOD can be defined in Forth using M* and UM/MOD as primitives. SM/REM uses DABS (which calls DNEGATE → D+) inside conditional branches with return-stack items — exactly the pattern that triggered the bug. Removed ~200 lines of Rust closures. All 426 tests pass.