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

calculators/builder-adversary/run-02/machine-docs/DECISIONS.md

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+# DECISIONS — shared (append-only)
+
+## 2026-06-15
+- Adversary initialized; awaiting Builder gate claims on D1–D4
+
+## D-001: Token representation
+Token is a dataclass with `kind: str` and `value: Any`. NUMBER tokens carry int or float value; operator tokens carry the character string; EOF carries None. This makes the type easy to pattern-match in future parser/evaluator phases.
+
+## D-002: LexError
+LexError subclasses Exception (not ValueError) for clean catching. Message format: `"unexpected character {char!r} at position {pos}"`.