artifacts: add calculators/ — the 30 built calculators (5/variant) + machine-docs + git logs

calculators/builder-adversary-lean/run-03/machine-docs/DECISIONS.md

@@ -0,0 +1,10 @@
+# DECISIONS (shared, append-only)
+
+_Phase: lex_
+
+## 2026-06-15
+
+- Token implemented as a dataclass with `kind: str` and `value` (int | float | str | None).
+- NUMBER tokens store int for integers, float for floats (not string).
+- EOF token has value None.
+- LexError is a plain Exception subclass defined in calc/lexer.py.