refactor(reverse-proxy): use route registry

lib/registry.nix

@@ -28,6 +28,10 @@ let
     in
     nameValuePair (registryName name) (import path { inherit lib; })
   ) (filterAttrs (name: type: type == "regular" && hasSuffix ".nix" name) (builtins.readDir (self + "/registry")));
+  join = registry: host: entry:
+    filterAttrs (_name: value: value != null) (
+      mapAttrs (registryName: _registry: (registry.${registryName}.${host} or { }).${entry} or null) definitions
+    );
 in
 {
   inherit definitions;
@@ -38,8 +42,14 @@ in
 
   collect =
     { hosts }:
-    mapAttrs (
-      registryName: _registry:
-      mapAttrs (hostName: host: host.config.registry.${registryName}.${hostName} or { }) hosts
-    ) definitions;
+    let
+      collected = mapAttrs (
+        registryName: _registry:
+        mapAttrs (hostName: host: host.config.registry.${registryName}.${hostName} or { }) hosts
+      ) definitions;
+    in
+    collected
+    // {
+      join = host: entry: join collected host entry;
+    };
 }