Docker HTTPS by default, smoke test improvements

Docker:
- HTTPS enabled by default (generates self-signed cert)
- Added docker-entrypoint.sh for SSL cert generation
- Gunicorn now starts with --certfile/--keyfile when HTTPS enabled
- Install curl/openssl in web container for healthcheck and certs
- Updated docs to reflect HTTPS default

Smoke Test:
- Moved from rpi/ to scripts/ (works for Pi, Docker, and dev)
- Updated header and examples
- Added to .gitignore exceptions

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

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

.gitignore

@@ -64,9 +64,10 @@ htmlcov/
 # Output test files.
 test_data/*.png
 
-# Dev scripts (local convenience scripts - except validate-release.sh)
+# Dev scripts (local convenience scripts - except these)
 scripts/*
 !scripts/validate-release.sh
+!scripts/smoke-test.sh
 
 # Web UI auth database and SSL certs
 instance/