[wifi] Place ap_ before the byte fields so they pack after it (#20138)

esphome/components/wifi/wifi_component.h

@@ -874,9 +874,6 @@ class WiFiComponent final : public Component {
 #ifdef WIFI_SCAN_RESULTS_LOCK_ENABLED
   Mutex scan_result_lock_;
 #endif
-#ifdef USE_WIFI_AP
-  WiFiAP ap_;
-#endif
 #ifdef USE_WIFI_IP_STATE_LISTENERS
   StaticVector<WiFiIPStateListener *, ESPHOME_WIFI_IP_STATE_LISTENERS> ip_state_listeners_;
 #endif
@@ -924,6 +921,9 @@ class WiFiComponent final : public Component {
   uint32_t roaming_scan_end_{0};  // Timestamp when last roaming scan completed
 #ifdef USE_WIFI_AP
   uint32_t ap_timeout_{90000};  // Keep in sync with DEFAULT_AP_TIMEOUT in __init__.py
+  // WiFiAP is byte aligned unless manual IP or EAP is enabled; placed before the
+  // 1-byte members so they pack into its trailing bytes instead of padding after it
+  WiFiAP ap_;
 #endif
 
   // 1-byte enums and integers