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

calculators/builder-adversary-deferred/run-04/machine-docs/BACKLOG-lex.md

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+# BACKLOG — lex phase
+
+## Build backlog
+
+- [x] D1 — NUMBER token for integers and floats (int/float value)
+- [x] D2 — PLUS, MINUS, STAR, SLASH, LPAREN, RPAREN, EOF tokens
+- [x] D3 — skip whitespace (space/tab); raise LexError on invalid char
+- [x] D4 — calc/test_lexer.py passing 20 unittest cases
+
+All items complete.
+
+## Adversary findings
+
+_(No findings yet.)_