Clean up debug scripts and update RPi docs

- Delete debug/diagnostic scripts (minimal_flask_crash.py, check_scipy.py)
- Delete old version summary markdown files
- Update RPi docs with default creds (admin/stegasoo)
- Add --soft flag documentation for sanitize script
- Switch compression from xz to zstd
- Add RPi image artifacts to .gitignore
- Improve sanitize-for-image.sh with validation and soft reset mode

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitignore

@@ -70,3 +70,10 @@ scripts/
 # Web UI auth database and SSL certs
 frontends/web/instance/
 frontends/web/certs/
+rpi/inject-wifi.sh
+
+# RPi image build artifacts
+*.img
+*.img.xz
+*.img.zst
+pishrink.sh