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

calculators/builder-adversary-deferred/run-01/machine-docs/BACKLOG-lex.md

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+# BACKLOG — phase `lex`
+
+## Build backlog
+
+All items completed.
+
+- [x] D1: Implement `NUMBER` token (int + float, including `.5` and `10.`)
+- [x] D2: Implement operator and paren tokens (`PLUS`, `MINUS`, `STAR`, `SLASH`, `LPAREN`, `RPAREN`)
+- [x] D3: Skip whitespace; raise `LexError` for invalid characters
+- [x] D4: Write `calc/test_lexer.py` with unittest coverage for D1–D3