feat: Implement server connections API and enhance GraphView with custom edge styling for improved visualization and user interaction in the topology graph.

backend/server.js

@@ -305,6 +305,20 @@ const serversRoutes = createJsonDataRoutes('servers.json', (server, i) => {
 app.get('/api/servers', serversRoutes.get);
 app.post('/api/servers', serversRoutes.post);
 
+// Server connections for topology graph
+const serverConnectionsRoutes = createJsonDataRoutes('server-connections.json', (conn, i) => {
+  if (!conn.from || !conn.to || !conn.tunnelType) {
+    return `Connection at index ${i} is missing required fields: from, to, tunnelType`;
+  }
+  if (conn.from === conn.to) {
+    return `Connection at index ${i} has identical from/to values`;
+  }
+  return null;
+});
+
+app.get('/api/server-connections', serverConnectionsRoutes.get);
+app.post('/api/server-connections', serverConnectionsRoutes.post);
+
 // Billing
 const billingRoutes = createJsonDataRoutes('servers-billing.json', (item, i) => {
   if (!item.hostName || !item.country || !item.provider) {