feat(core-eslint): rule no-realtime-handler-reexport

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/core-eslint/base.js

@@ -5,6 +5,7 @@ import turboPlugin from "eslint-plugin-turbo";
 import boundaries from "eslint-plugin-boundaries";
 import globals from "globals";
 import noDirectSocketIO from "./rules/no-direct-socket-io.js";
+import noRealtimeHandlerReexport from "./rules/no-realtime-handler-reexport.js";
 
 export default [
   { ignores: ["dist/**", "node_modules/**", ".next/**", ".turbo/**", "storybook-static/**"] },
@@ -172,11 +173,20 @@ export default [
   },
   // R2 — `socket.io` and `socket.io-client` must not be imported outside
   // core-realtime/src/ and apps/*/server.ts. Use @repo/core-realtime helpers.
+  // R1 (ADR-016) — Realtime handlers must not be re-exported outside bind-* files.
   {
     files: ["**/*.{ts,tsx,mjs,cjs,js}"],
-    plugins: { "repo-rules": { rules: { "no-direct-socket-io": noDirectSocketIO } } },
+    plugins: {
+      "repo-rules": {
+        rules: {
+          "no-direct-socket-io": noDirectSocketIO,
+          "no-realtime-handler-reexport": noRealtimeHandlerReexport,
+        },
+      },
+    },
     rules: {
       "repo-rules/no-direct-socket-io": "error",
+      "repo-rules/no-realtime-handler-reexport": "error",
     },
   },
 ];