Move memory allocation words to boot.fth:
- ALLOT: `: ALLOT HERE + 12 ! ;`
- , (comma): `: , HERE ! 1 CELLS ALLOT ;`
- C, : `: C, HERE C! 1 ALLOT ;`
- ALIGN: `: ALIGN HERE ALIGNED 12 ! ;`
- FALIGN, SFALIGN, DFALIGN: float-aligned variants
These write directly to WASM memory[SYSVAR_HERE]. The Rust side picks up
Forth-side HERE changes via refresh_user_here() which now reads both
here_cell (for Rust host functions) and memory[12] (for Forth words),
taking the maximum to ensure no allocation is lost.
Removed 222 lines of Rust. All 426 tests pass.
ok2
b7256e3130