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

calculators/builder-adversary-stateless/run-04/machine-docs/JOURNAL-lex.md

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+# JOURNAL — phase lex
+
+## Build session
+
+### Design decisions
+- `Token` is a `dataclass` with `kind: str` and `value: Union[int, float, None]`. Operator tokens have `value=None`; `NUMBER` tokens carry their parsed numeric value (int for integers, float when `.` present).
+- `LexError` is a plain `Exception` subclass defined in the module.
+- Used `re` module with `_NUMBER_RE = re.compile(r'\d+\.?\d*|\.\d+')` to match integers, floats-with-integer-part, and leading-dot floats.
+- `_SINGLE` dict maps single chars to token kinds.
+
+### Test run output
+```
+python -m unittest -q
+----------------------------------------------------------------------
+Ran 17 tests in 0.000s
+
+OK
+```
+
+### Verify command outputs
+```
+python -c "from calc.lexer import tokenize; print([(t.kind,t.value) for t in tokenize('3.5*(1-2)')])"
+[('NUMBER', 3.5), ('STAR', None), ('LPAREN', None), ('NUMBER', 1), ('MINUS', None), ('NUMBER', 2), ('RPAREN', None), ('EOF', None)]
+
+python -c "from calc.lexer import tokenize; tokenize('1 @ 2')"
+Traceback (most recent call last):
+  ...
+calc.lexer.LexError: unexpected character '@' at position 2
+```