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

calculators/builder-solo/run-02/machine-docs/JOURNAL-lex.md

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+# JOURNAL-lex
+
+## 2026-06-15
+
+### Build
+- Created `calc/__init__.py` (empty package marker)
+- Created `calc/lexer.py`: `Token` (NamedTuple with `kind` and `value`), `LexError`, `tokenize(src)`
+  - Handles integers (int), floats (float, including `.5` and `10.` edge cases)
+  - Single-char operators: `+ - * / ( )`
+  - Whitespace (space, tab) skipped
+  - Invalid chars raise `LexError` with char repr and position
+  - Appends `EOF` token at end
+- Created `calc/test_lexer.py`: 14 unittest cases covering D1–D3
+
+### Verification
+- `python -m unittest -q` → 14 tests, 0 failures — PASS
+- `tokenize('3.5*(1-2)')` → correct 8-token sequence — PASS
+- `tokenize('1 @ 2')` → raises `LexError: unexpected character '@' at position 2` — PASS
+
+### Commit
+`7ac5cdaded6af3b635d6d638f9c20082b5648393`