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/fr/micropython.py

@@ -0,0 +1,11 @@
+from machine import Pin
+from time import sleep
+
+# Définit la broche 2 en sortie (généralement la LED intégrée)
+led = Pin(2, Pin.OUT)
+
+while True:
+    led.value(1)  # Allume la LED
+    sleep(0.5)    # Attend 0,5 seconde
+    led.value(0)  # Éteint la LED
+    sleep(0.5)    # Attend 0,5 seconde