feat: edge gateway service

gateway/docs/README.md

@@ -0,0 +1,20 @@
+# Edge Gateway Docs
+
+This directory keeps service-local documentation that is too detailed for the
+root architecture documents and too diagram-heavy for the module README.
+
+Sections:
+
+- [Runtime and components](runtime.md)
+- [Public auth, command, and push flows](flows.md)
+- [Operator runbook](runbook.md)
+- [Configuration and contract examples](examples.md)
+- [Example `.env`](../.env.example)
+
+Primary references:
+
+- [`../README.md`](../README.md) for service scope, contracts, configuration,
+  and operational behavior
+- [`../openapi.yaml`](../openapi.yaml) for the public REST contract
+- [`../../README.md`](../../README.md) for workspace-level architecture
+- [`../../SECURITY.md`](../../SECURITY.md) for the transport security model