Expand API and deployment documentation

examples/CustomPortalContent/CustomPortalContent.ino

@@ -28,6 +28,7 @@ void setup() {
     portal.portalAddHomeCard(hint);
 
     portal.setSaveParamsCallback([](WiFiManager::WiFiManagerRequestArgs) {
+        // A product validates and persists this value here; this demo only prints it.
         Serial.print("MQTT broker selected: ");
         Serial.println(brokerHost.getValue());
     });

examples/CustomPortalContent/README.md

@@ -10,4 +10,4 @@ It opens **WiFiManager Content** with password **example-pass** until it has wor
 
 The parameter object is global because WiFiManager reads it for the lifetime of the portal. In a real application, copy the value into that application’s own validated persistent configuration inside the save callback.
 
-See [structured portal content](../../docs/PORTAL_UI.md#structured-portal-content) and the shared [example guide](../README.md).
+See [Portal content](../../docs/PORTAL_CONTENT.md), [product settings and Wi-Fi](../../docs/recipes/PRODUCT_SETTINGS_AND_WIFI.md), and the shared [example guide](../README.md).