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

calculators/builder-adversary-lean/run-05/machine-docs/DECISIONS.md

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+# DECISIONS (append-only, shared)
+
+## lex phase
+
+### Token type
+Used a simple class with `__slots__` for efficiency and `__eq__` for easy test assertions. No namedtuple to allow future extension (e.g. position tracking for later phases).
+
+### Number regex
+`r'\d+\.?\d*|\.\d+'` — handles `42`, `3.14`, `10.`, `.5`. The alternation order matters: longest match first via `re.match` at position `i`.
+
+### EOF token
+`Token('EOF', None)` — value is None since EOF carries no semantic content; downstream parser phases can type-check on `kind == 'EOF'`.