chore: ignore .env, local agent notes, and native setup artifacts

setup.sh writes Bambu Lab credentials and DJANGO_SECRET_KEY into .env,
which was previously untracked but not ignored — one 'git add .' away
from being committed. Also ignores .venv/, data/, db.sqlite3, and
CLAUDE.local.md.

.gitignore

@@ -1,2 +1,27 @@
+# Secrets — setup.sh writes Bambu credentials + Django secret key here
+.env
+!.env.example
+
+# Local-only agent notes
+CLAUDE.local.md
+.claude/
+
+# Native setup artifacts
+.venv/
+data/
+db.sqlite3
+staticfiles/
+
+# Python
+__pycache__/
+*.py[cod]
+*.egg-info/
+build/
+dist/
+
+# Editors / OS
+.idea/
+.vscode/
+.DS_Store
 
 .worktrees/