Refine Wi-Fi, mDNS, and terminal lifecycles

- Stage disabled station profile edits without restarting the radio
- Make mDNS initialization failure-isolated and reannounce in place
- Document deferred admin actions and explicit browser disconnect
  behavior

src/mdns_service.c

@@ -12,6 +12,8 @@
 
 static SemaphoreHandle_t s_mutex;
 static mdns_config_t s_config;
+static bool s_component_initialized;
+static bool s_initialization_failed;
 static bool s_announced;
 static esp_err_t s_last_error;
 
@@ -91,10 +93,16 @@ esp_err_t mdns_service_start(void)
         return ESP_ERR_INVALID_STATE;
     }
     lock_service();
-    if (s_announced) {
+    if (s_component_initialized) {
+        s_announced = true;
         unlock_service();
         return ESP_OK;
     }
+    if (s_initialization_failed) {
+        esp_err_t error = s_last_error;
+        unlock_service();
+        return error;
+    }
     mdns_config_t config = s_config;
     unlock_service();
 
@@ -112,6 +120,8 @@ esp_err_t mdns_service_start(void)
     }
 
     lock_service();
+    s_component_initialized = error == ESP_OK;
+    s_initialization_failed = error != ESP_OK;
     s_announced = error == ESP_OK;
     s_last_error = error;
     unlock_service();
@@ -124,10 +134,30 @@ void mdns_service_stop(void)
         return;
     }
     lock_service();
-    bool announced = s_announced;
     s_announced = false;
     unlock_service();
-    if (announced) {
-        mdns_free();
-    }
+}
+
+esp_err_t mdns_service_reannounce(void)
+{
+    if (s_mutex == NULL) {
+        return ESP_ERR_INVALID_STATE;
+    }
+    lock_service();
+    if (!s_component_initialized) {
+        esp_err_t error = s_initialization_failed ? s_last_error : ESP_ERR_INVALID_STATE;
+        unlock_service();
+        return error;
+    }
+    mdns_config_t config = s_config;
+    unlock_service();
+
+    char hostname[MDNS_CONFIG_SUFFIX_MAX_LEN + 5U] = {0};
+    make_hostname(&config, hostname, sizeof(hostname));
+    esp_err_t error = mdns_hostname_set(hostname);
+
+    lock_service();
+    s_last_error = error;
+    unlock_service();
+    return error;
 }