volt: untrack 19 redundant .pyc (105,528 B, source at HEAD) + first .gitignore; residue_check.py grades the class

.gitignore

@@ -0,0 +1,23 @@
+# Derived artifacts never enter this archive. Added 2026-10-23 (volt, Workhorse)
+# after the tree carried nineteen tracked .pyc files and no ignore rule at all:
+# every Python or editor run inside the checkout recreates these, so a rule here
+# is the only thing that keeps the tree clean between ticks. Nothing in this
+# list is content a reader can review, diff or re-run.
+__pycache__/
+*.py[cod]
+.pytest_cache/
+.mypy_cache/
+.ruff_cache/
+.tox/
+htmlcov/
+.coverage
+.coverage.*
+coverage.xml
+node_modules/
+.DS_Store
+*~
+*.swp
+*.swo
+*.orig
+*.rej
+*.bak