Initial commit: krust - container image build tool for Rust

krust builds container images for Rust applications without Docker:
- Builds static binaries using musl libc
- Creates minimal OCI container images
- Pushes to any OCI-compliant registry
- Outputs digest to stdout for composability

Inspired by ko.build for Go applications.

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

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

example/hello-krust/src/main.rs

@@ -0,0 +1,4 @@
+fn main() {
+    println!("Hello from krust example!");
+    println!("This is running inside a container built with krust.");
+}