Add custom Iroh relay maps

docs/architecture.md

@@ -25,7 +25,10 @@ a transitive `ed25519-dalek` prerelease dependency. `geth-iroh` wraps
 `Builder::relay_mode`, persists an `iroh::SecretKey` as hex-encoded 32-byte key
 material, and shuts down through `Endpoint::close().await`. The default config
 uses Iroh's default relay policy; local-only/offline development can set
-`[iroh].relay_mode = "disabled"`.
+`[iroh].relay_mode = "disabled"`. Named custom relay maps are configured under
+`[iroh.relay_maps.<name>]`, selected with `relay_mode = "custom"` plus
+`relay_map = "<name>"`, validated at config load, and reported in status as
+`custom:<name>` without exposing relay URLs.
 
 Module ALPNs are registered through `geth-iroh`'s protocol router scaffold. The
 router owns the default protocol descriptors, rejects duplicate ALPN

docs/roadmap.md

@@ -81,7 +81,7 @@ geth-to-geth connections without granting trust from discovery alone.
   - `geth status --json` reports the selected relay mode.
   - Tests cover config parsing and endpoint builder relay-mode selection.
 
-- `[ ]` Custom relay maps.
+- `[x]` Custom relay maps.
   Acceptance criteria:
   - Config can define and select named custom relay maps.
   - Invalid relay URLs fail config validation with clear errors.