chore: repo hygiene — move report/ + private/ out, gitignore report/

- Audit reports moved to ~/thetadx-reports (not source-tracked)
- /private moved to ~/private (per user; was their workspace mess)
- report/ added to .gitignore so future audit drops don't pollute

Author: userFRM

.gitignore

@@ -22,3 +22,4 @@ private/
 artifacts/
 todo.md
 out/
+report/