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-nn.c

@@ -0,0 +1,44 @@
+#include <stdio.h>
+#include "esp_nn.h"
+#include "esp_nn_defs.h"
+
+#define INPUT_SIZE 4
+#define OUTPUT_SIZE 3
+
+void print_array(const char *label, int16_t *array, int size) {
+    printf("%s: ", label);
+    for (int i = 0; i < size; i++) {
+        printf("%d ", array[i]);
+    }
+    printf("\n");
+}
+
+void app_main(void)
+{
+    // Vetor de entrada (ex: saída de uma camada anterior)
+    int16_t input[INPUT_SIZE] = {1, 2, 3, 4};
+
+    // Pesos da camada densa (3x4)
+    int8_t weights[OUTPUT_SIZE * INPUT_SIZE] = {
+         1, -1,  2,  0,
+         0,  1, -1,  1,
+         2,  0,  1, -2
+    };
+
+    // Bias de cada neurônio
+    int16_t bias[OUTPUT_SIZE] = {10, -5, 0};
+
+    // Saída
+    int16_t output[OUTPUT_SIZE];
+
+    // Multiplicação da matriz: output = weights * input + bias
+    esp_nn_mul_mat_16x8_16(weights, input, bias, output,
+                           OUTPUT_SIZE, INPUT_SIZE, /*shift=*/0);
+
+    print_array("Antes da ReLU", output, OUTPUT_SIZE);
+
+    // Aplicar função de ativação ReLU
+    esp_nn_relu_16(output, OUTPUT_SIZE);
+
+    print_array("Depois da ReLU", output, OUTPUT_SIZE);
+}