fix(SEC-WEB-37): Gate federation mock data behind NODE_ENV check

Replace exported const mockConnections with getMockConnections() function
that returns mock data only when NODE_ENV === "development". In production
and test environments, returns an empty array as defense-in-depth alongside
the existing ComingSoon page gate (SEC-WEB-4).

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

apps/web/src/app/(authenticated)/federation/connections/page.tsx

@@ -10,7 +10,7 @@ import { ConnectionList } from "@/components/federation/ConnectionList";
 import { InitiateConnectionDialog } from "@/components/federation/InitiateConnectionDialog";
 import { ComingSoon } from "@/components/ui/ComingSoon";
 import {
-  mockConnections,
+  getMockConnections,
   FederationConnectionStatus,
   type ConnectionDetails,
 } from "@/lib/api/federation";
@@ -54,7 +54,7 @@ function ConnectionsPageContent(): React.JSX.Element {
 
       // Using mock data for now (development only)
       await new Promise((resolve) => setTimeout(resolve, 500)); // Simulate network delay
-      setConnections(mockConnections);
+      setConnections(getMockConnections());
     } catch (err) {
       setError(
         err instanceof Error ? err.message : "Unable to load connections. Please try again."