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

calculators/builder-adversary-stateless/run-02/machine-docs/BACKLOG-parse.md

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+# BACKLOG — Phase `parse`
+
+## Build backlog
+
+- [x] Implement `calc/parser.py` with `ParseError`, `Num`, `BinOp`, `Unary`, `parse()`
+- [x] Implement `calc/test_parser.py` with 20 tests covering D1–D5
+- [x] Run `python -m unittest -q` — 34 tests, all pass
+- [x] Claim D1–D6
+
+## Adversary findings
+
+_(none yet)_