Add vendor assets, fix CLI imports, make web UI bootable

- Copy Bootstrap 5, Bootstrap Icons, and html5-qrcode from stegasoo
- Fix stegasoo CLI import (cli group, not main wrapper)
- Add .gitignore and README.md
- Verified: soosef init, soosef serve, all routes, key export/import all work

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,15 @@
+__pycache__/
+*.pyc
+*.egg-info/
+dist/
+build/
+*.egg
+.eggs/
+venv/
+.venv/
+*.swp
+*.swo
+.mypy_cache/
+.pytest_cache/
+.ruff_cache/
+instance/