docs: document layer rules

Author: spacemeowx2

README.md

@@ -16,6 +16,17 @@
 
 All-in-one proxy written in Rust.
 
+## Layer Rules
+
+This repo follows a simple Clean/Hex-ish layering:
+
+- **Domain**: `rd-interface`, `rd-derive` (traits/types/derive only; no concrete implementations)
+- **Core**: `rabbit-digger` (runtime/orchestration; depends only on Domain)
+- **Adapters**: `rd-std`, `protocol/*` (concrete nets/servers; depend on Domain)
+- **App**: `rabbit-digger-pro` (CLI/API/config; composes everything via a bundle)
+
+Dependency direction is enforced in CI via `depguard`.
+
 ## Features
 
 * Hot reloading: Apply changes without restart the program.

agent-docs/ARCH_REFACTOR_PLAN.md

@@ -60,7 +60,7 @@ This document turns the proposed Clean/Hex refactor into a commit-friendly check
 ## 4) Guardrails (recommended)
 
 - [x] Add CI checks for dependency direction (e.g. `cargo tree -i` patterns or `cargo deny`).
-- [ ] Add a short “layer rules” section to README.
+- [x] Add a short “layer rules” section to README.
 - [ ] Prefer `pub(crate)` for app-internal modules; keep Domain/Core public APIs minimal.
 
 ## 5) Execution Order (what I will do next)