1482d7513e
Create boot.fth loaded at startup after IR primitives are compiled. Forth-compiled WASM with direct calls outperforms host function dispatch (no call_indirect overhead, Cranelift can inline across word boundaries). Words moved to Forth: 2OVER, 2ROT, WITHIN, 2@, 2!, FILL, CMOVE, CMOVE>, MOVE, ERASE, BLANK, /STRING, -TRAILING. Removed 547 lines of Rust closures, replaced by 48 lines of Forth. All 425 tests pass.