Harden local runtime safety and error handling

bible-local/05-config.md

@@ -41,7 +41,7 @@ Rules:
 
 ```yaml
 server:
-  host: "0.0.0.0"
+  host: "127.0.0.1"
   port: 8080
   mode: "release"   # release | debug
 
@@ -54,6 +54,9 @@ backup:
   time: "00:00"     # HH:MM in local time
 ```
 
+`server.host` must stay on loopback (`127.0.0.1`, `localhost`, or `::1`).
+QuoteForge startup rejects non-loopback bind addresses because the local client has no auth/RBAC perimeter.
+
 ---
 
 ## Environment Variables