Ignore the .scratch working directory

.scratch/ holds throwaway diagnostic scripts and captured fixtures from
debugging sessions against the live instance --- including a 200 kB screenshot.
None of it belongs in history, but it sat untracked in every `git status`,
one `git add -A` away from being committed by accident.

The files are left on disk; only the path is ignored.

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

.gitignore

@@ -7,3 +7,4 @@ venv/
 dist/
 build/
 .env
+.scratch/