feat: project skeleton, CLI surface, generate command, secret redaction, and CI matrix

- Create Rust binary crate with clap CLI (listen, connect, generate, version)
- Implement generate command: CA/server/client certs, auth token, config.json
- Strict secret redaction: Redacted type, PEM/token/config redaction utilities
- Configurable addresses and ports with validation (fails before sockets open)
- GitHub Actions CI matrix: Windows/Linux/macOS with fmt, clippy, test, build,
  release-build, and smoke check jobs
- 39 unit tests covering CLI parsing, redaction, config, and credential generation
- Cross-platform safe paths and clean-room implementation

.gitignore

@@ -0,0 +1,6 @@
+/target
+Cargo.lock
+**/*.pem
+**/*.json
+.env
+*.log