ignore the venv and local tool state

On klone the venv is created inside the repo with create_cdsc_venv, so
it otherwise shows up as untracked in every git status. Claude Code
keeps its per-project permission list in .claude/settings.local.json,
which is personal to whoever is running it, and writes it atomically via
sibling temp files, so the pattern covers those too. Only that file is
ignored, leaving room to commit a shared .claude/settings.json later.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.gitignore

@@ -10,6 +10,11 @@ uv.lock
 # JetBrains
 /.idea
 
+/.claude/settings.local.json*
+
 # Python build and test output
 __pycache__/
 /test/test_output/
+
+# Virtualenv (created with create_cdsc_venv on klone)
+/.venv/