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

calculators/builder-adversary-lean/run-03/machine-docs/JOURNAL-eval.md

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+# JOURNAL — eval phase
+
+## 2026-06-15
+
+### Implementation approach
+
+Read the existing lexer/parser to understand AST node shapes: `Num(value)`, `BinOp(op, left, right)`, `Unary(op, operand)`.
+
+Implemented `calc/evaluator.py`:
+- `EvalError(Exception)` — wraps division-by-zero and unknown nodes; never lets `ZeroDivisionError` escape.
+- `evaluate(node)` — recursive AST walk; delegates to `_coerce` after each operation.
+- `_coerce(value)` — if `isinstance(value, float) and value == int(value)` → return `int(value)`; else return value as-is. This is the D3 rule applied uniformly at every arithmetic result.
+
+Created `calc/test_evaluator.py` with 20 tests across 3 test classes (TestArithmetic, TestDivision, TestResultType).
+
+Created top-level `calc.py` CLI: parses one arg, catches `LexError | ParseError | EvalError`, prints to stderr + exits 1 on error, prints result + exits 0 on success.
+
+### Test run output
+
+```
+$ python -m unittest -q
+Ran 68 tests in 0.001s
+OK
+```
+
+### CLI spot-checks
+
+```
+$ python calc.py "2+3*4"
+14
+$ python calc.py "(2+3)*4"
+20
+$ python calc.py "7/2"
+3.5
+$ python calc.py "4/2"
+2
+$ python calc.py "1/0"
+error: division by zero
+(exit 1)
+$ python calc.py "1 +"
+error: unexpected token 'EOF' (None)
+(exit 1)
+```