fix(openwrt): allow No router/OpenWrt errors through RPC sanitizer

Without these prefixes in the allowlist, sanitize_error_message swallowed
the "No router configured" error and returned a generic "Operation failed",
so the frontend could never detect the unconfigured state and show the
connect form.

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

core/archipelago/src/api/rpc/middleware.rs

@@ -64,6 +64,8 @@ pub(super) fn sanitize_error_message(msg: &str) -> String {
         "Container",
         "Image",
         "Bitcoin address",
+        "No router",
+        "No OpenWrt",
     ];
     for prefix in &user_facing_prefixes {
         if msg.starts_with(prefix) {