Add comprehensive Podman secrets support to prevent credential exposure:
New types and methods (internal/container/podman.go):
- PodmanSecret struct for secret definitions
- CreateSecret() - Create Podman secrets from sensitive data
- DeleteSecret() - Clean up secrets after use
- BuildSecretArgs() - Generate podman run arguments for secrets
- SanitizeContainerEnv() - Extract sensitive env vars as secrets
- ContainerConfig.Secrets field for secret list
Enhanced container lifecycle:
- StartContainer() now creates secrets before starting container
- Secrets automatically mounted via --secret flag
- Cleanup on failure to prevent secret leakage
- Secrets logged as count only (not content)
Jupyter service integration (internal/jupyter/service_manager.go):
- prepareContainerConfig() uses SanitizeContainerEnv()
- JUPYTER_TOKEN and JUPYTER_PASSWORD now use secrets
- Maintains backward compatibility with env var mounting
Security benefits:
- Credentials no longer visible in 'podman inspect' output
- Secrets not exposed via /proc/*/environ inside container
- Automatic cleanup prevents secret accumulation
- Compatible with existing Jupyter authentication
- Add stripTokenFromURL() helper function to remove tokens from URLs
- Use it when logging service start URLs
- Use it when logging connectivity test URLs
- Prevents sensitive tokens from being written to log files
- Move ci-test.sh and setup.sh to scripts/
- Trim docs/src/zig-cli.md to current structure
- Replace hardcoded secrets with placeholders in configs
- Update .gitignore to block .env*, secrets/, keys, build artifacts
- Slim README.md to reflect current CLI/TUI split
- Add cleanup trap to ci-test.sh
- Ensure no secrets are committed
