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

calculators/builder-solo/run-04/machine-docs/JOURNAL-parse.md

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+# JOURNAL-parse
+
+## Session 1
+
+Built `calc/parser.py` — recursive-descent parser with grammar:
+- `expr → term (('+' | '-') term)*`
+- `term → unary (('*' | '/') unary)*`
+- `unary → '-' unary | primary`
+- `primary → NUMBER | '(' expr ')'`
+
+Left associativity achieved via iterative loops (not recursion) in `expr` and `term`.
+Unary minus handled in its own `unary` rule, which recurses right.
+
+Built `calc/test_parser.py` with 19 tests (35 total including lex tests) covering D1–D5.
+
+All DoD gates passed on first run.