feat(i18n): routing and localization infrastructure (phase 1)

Implement Phase 1 of i18n spec:
- Configure next-intl with 6 locales (pt, en, es, fr, de, zh-CN) and pathnames
- Move routes to app/[locale] structure with localized layouts and metadata
- Add middleware for root language negotiation (307), legacy redirects (308), and 404 for non-pt book
- Implement language selector dropdown in header with cookie persistence
- Add system typography rules for zh-CN and word-break/hyphenation for de/fr

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

i18n/routing.js

@@ -0,0 +1,101 @@
+import { defineRouting } from "next-intl/routing";
+
+export const routing = defineRouting({
+	locales: ["pt", "en", "es", "fr", "de", "zh-CN"],
+	defaultLocale: "en",
+	localePrefix: "always",
+	pathnames: {
+		"/": "/",
+		"/series": {
+			pt: "/series",
+			en: "/series",
+			es: "/series",
+			fr: "/series",
+			de: "/serien",
+			"zh-CN": "/series",
+		},
+		"/series/[key]": {
+			pt: "/series/[key]",
+			en: "/series/[key]",
+			es: "/series/[key]",
+			fr: "/series/[key]",
+			de: "/serien/[key]",
+			"zh-CN": "/series/[key]",
+		},
+		"/catalogo": {
+			pt: "/catalogo",
+			en: "/catalog",
+			es: "/catalogo",
+			fr: "/catalogue",
+			de: "/katalog",
+			"zh-CN": "/catalog",
+		},
+		"/comparacao": {
+			pt: "/comparacao",
+			en: "/compare",
+			es: "/comparacion",
+			fr: "/comparaison",
+			de: "/vergleich",
+			"zh-CN": "/compare",
+		},
+		"/componentes": {
+			pt: "/componentes",
+			en: "/components",
+			es: "/componentes",
+			fr: "/composants",
+			de: "/komponenten",
+			"zh-CN": "/components",
+		},
+		"/diagnostico": {
+			pt: "/diagnostico",
+			en: "/diagnostics",
+			es: "/diagnostico",
+			fr: "/diagnostic",
+			de: "/diagnose",
+			"zh-CN": "/diagnostics",
+		},
+		"/frameworks": {
+			pt: "/frameworks",
+			en: "/frameworks",
+			es: "/frameworks",
+			fr: "/frameworks",
+			de: "/frameworks",
+			"zh-CN": "/frameworks",
+		},
+		"/frameworks/[key]": {
+			pt: "/frameworks/[key]",
+			en: "/frameworks/[key]",
+			es: "/frameworks/[key]",
+			fr: "/frameworks/[key]",
+			de: "/frameworks/[key]",
+			"zh-CN": "/frameworks/[key]",
+		},
+		"/glossario": {
+			pt: "/glossario",
+			en: "/glossary",
+			es: "/glosario",
+			fr: "/glossaire",
+			de: "/glossar",
+			"zh-CN": "/glossary",
+		},
+		"/seletor": {
+			pt: "/seletor",
+			en: "/selector",
+			es: "/selector",
+			fr: "/selecteur",
+			de: "/auswahl",
+			"zh-CN": "/selector",
+		},
+		"/sobre": {
+			pt: "/sobre",
+			en: "/about",
+			es: "/acerca",
+			fr: "/a-propos",
+			de: "/ueber-uns",
+			"zh-CN": "/about",
+		},
+		"/livro": {
+			pt: "/livro",
+		},
+	},
+});