feat(i18n): French and German localization (phase 5)

- Add full message catalogs and content for French (fr) and German (de)
- Implement ASCII canonical slugs for French and German routes
- Add language-specific search endpoints (/api/busca/fr, /api/busca/de)
- Configure strict 404 responses for /fr/livro and /de/livro
- Localize SEO, OpenGraph (fr_FR, de_DE), Twitter and JSON-LD schemas
- Add localized code example comments across 14 examples for fr and de
- Enable 'fr' and 'de' in ENABLED_LOCALES with root negotiation and redirect
- Extend test suite in check-i18n, smoke-imagem and verifica-vazamentos

Co-Authored-By: Antigravity <noreply@google.com>

public/exemplos/de/esp-rainmaker.c

@@ -0,0 +1,76 @@
+/*
+ * Exemplo ESP-RainMaker para ESP32
+ * Dispositivo: Interruptor Inteligente com controle via App e Nuvem
+ * 
+ * Dependência (idf_component.yml):
+ *   espressif/esp_rainmaker: "^1.4.0"
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "esp_log.h"
+#include "nvs_flash.h"
+
+#include <esp_rmaker_core.h>
+#include <esp_rmaker_standard_params.h>
+#include <esp_rmaker_standard_devices.h>
+#include <app_wifi.h>
+
+static const char *TAG = "app_rainmaker";
+static esp_rmaker_device_t *switch_device;
+
+/* Callback acionado quando o usuário altera o estado no App móvel */
+static esp_err_t write_cb(const esp_rmaker_device_t *dev, const esp_rmaker_param_val_t val, void *priv_data, esp_rmaker_write_ctx_t *ctx)
+{
+    if (ctx) {
+        ESP_LOGI(TAG, "Comando recebido via %s", esp_rmaker_device_cb_src_to_str(ctx->src));
+    }
+    
+    bool state = val.val.b;
+    ESP_LOGI(TAG, "Schalterzustand geändert auf: %s", state ? "EIN" : "AUS");
+    
+    // Aktualisiert den Parameter in Cloud und App
+    esp_rmaker_param_update_and_report(priv_data, val);
+    return ESP_OK;
+}
+
+void app_main(void)
+{
+    // Inicialização da memória não-volátil (NVS)
+    esp_err_t err = nvs_flash_init();
+    if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+        ESP_ERROR_CHECK(nvs_flash_erase());
+        err = nvs_flash_init();
+    }
+    ESP_ERROR_CHECK(err);
+
+    // Inicializa o provisionamento Wi-Fi
+    app_wifi_init();
+
+    // Configura o nó RainMaker
+    esp_rmaker_config_t rainmaker_cfg = {
+        .enable_time_sync = true,
+    };
+    esp_rmaker_node_t *node = esp_rmaker_node_init(&rainmaker_cfg, "ESP32_SmartSwitch", "Switch");
+    
+    // Cria o dispositivo padrão 'Switch'
+    switch_device = esp_rmaker_switch_device_create("Luz Sala", NULL, true);
+    
+    // Registra callback de escrita
+    esp_rmaker_device_add_cb(switch_device, write_cb, NULL);
+    esp_rmaker_node_add_device(node, switch_device);
+
+    // Habilita serviços adicionais (OTA e Timezone)
+    esp_rmaker_ota_enable_default();
+    esp_rmaker_timezone_service_enable();
+
+    // Inicia o agente RainMaker
+    esp_rmaker_start();
+
+    // Inicia o provisionamento Wi-Fi via BLE (abre no app oficial RainMaker)
+    app_wifi_start(POP_TYPE_RANDOM);
+
+    ESP_LOGI(TAG, "Nó RainMaker pronto! Escaneie o QR Code no app ESP RainMaker.");
+}