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>

app/[locale]/layout.jsx

@@ -0,0 +1,162 @@
+import { notFound } from "next/navigation";
+import { JetBrains_Mono, Manrope, Space_Grotesk } from "next/font/google";
+import { NextIntlClientProvider } from "next-intl";
+import { getMessages } from "next-intl/server";
+import { routing } from "@/i18n/routing";
+import "../globals.css";
+import Providers from "@/components/Providers";
+import { SITE, jsonLd } from "@/lib/seo";
+
+const spaceGrotesk = Space_Grotesk({
+	subsets: ["latin"],
+	variable: "--font-space-grotesk",
+	display: "swap",
+	weight: ["500", "600", "700"],
+});
+
+const manrope = Manrope({
+	subsets: ["latin"],
+	variable: "--font-manrope",
+	display: "swap",
+	weight: ["400", "500", "600", "700"],
+});
+
+const jetbrainsMono = JetBrains_Mono({
+	subsets: ["latin"],
+	variable: "--font-jetbrains",
+	display: "swap",
+	weight: ["400", "500", "600"],
+});
+
+const LANG_MAP = {
+	pt: "pt-BR",
+	en: "en",
+	es: "es-419",
+	fr: "fr",
+	de: "de",
+	"zh-CN": "zh-CN",
+};
+
+export function generateStaticParams() {
+	return routing.locales.map((locale) => ({ locale }));
+}
+
+export async function generateMetadata({ params }) {
+	const { locale } = await params;
+	const ogLocaleMap = {
+		pt: "pt_BR",
+		en: "en_US",
+		es: "es_419",
+		fr: "fr_FR",
+		de: "de_DE",
+		"zh-CN": "zh_CN",
+	};
+
+	return {
+		metadataBase: new URL(SITE.url),
+		title: {
+			default: "ESPDocs · Documentação do ESP32 em português",
+			template: "%s · ESPDocs",
+		},
+		description:
+			"Especificações, pinagem, comparação e seleção das 12 séries de microcontroladores ESP32, em português brasileiro. Datasheets, periféricos, segurança em hardware e diagramas de conexão.",
+		applicationName: "ESPDocs",
+		authors: [{ name: "Lucas Rayan Guerra", url: "https://lucasrguerra.dev.br" }],
+		creator: "Lucas Rayan Guerra",
+		publisher: "Ciência Embarcada",
+		category: "technology",
+		keywords: [
+			"ESP32", "ESP32 português", "documentação ESP32", "pinout ESP32",
+			"ESP32-S3", "ESP32-C3", "ESP32-C6", "ESP32-P4", "ESP32-H2",
+			"comparar ESP32", "qual ESP32 escolher", "datasheet ESP32",
+			"microcontrolador", "Espressif", "ESP-IDF", "IoT", "sistemas embarcados",
+		],
+		alternates: { canonical: `/${locale}` },
+		openGraph: {
+			type: "website",
+			locale: ogLocaleMap[locale] || "pt_BR",
+			url: `${SITE.url}/${locale}`,
+			siteName: SITE.nome,
+			title: "ESPDocs · Documentação do ESP32 em português",
+			description:
+				"Especificações, pinagem, comparação e seleção das 12 séries de microcontroladores ESP32, em português brasileiro.",
+		},
+		twitter: {
+			card: "summary_large_image",
+			title: "ESPDocs · Documentação do ESP32 em português",
+			description:
+				"Especificações, pinagem, comparação e seleção das 12 séries de ESP32, em português.",
+		},
+		robots: {
+			index: true,
+			follow: true,
+			googleBot: {
+				index: true,
+				follow: true,
+				"max-image-preview": "large",
+				"max-snippet": -1,
+				"max-video-preview": -1,
+			},
+		},
+		icons: {
+			icon: [
+				{ url: "/favicon.ico", sizes: "48x48", type: "image/x-icon" },
+				{ url: "/favicon-48x48.png", sizes: "48x48", type: "image/png" },
+				{ url: "/favicon-32x32.png", sizes: "32x32", type: "image/png" },
+				{ url: "/favicon-16x16.png", sizes: "16x16", type: "image/png" },
+				{ url: "/icon-192.png", sizes: "192x192", type: "image/png" },
+				{ url: "/icon-512.png", sizes: "512x512", type: "image/png" },
+				{ url: "/icon.svg", type: "image/svg+xml" },
+			],
+			apple: [
+				{ url: "/apple-touch-icon.png", sizes: "180x180", type: "image/png" },
+			],
+			shortcut: "/favicon.ico",
+		},
+		manifest: "/site.webmanifest",
+		formatDetection: { telephone: false, address: false, email: false },
+	};
+}
+
+export const viewport = {
+	themeColor: [
+		{ media: "(prefers-color-scheme: light)", color: "#f5f6f8" },
+		{ media: "(prefers-color-scheme: dark)", color: "#07090d" },
+	],
+};
+
+export default async function RootLayout({ children, params }) {
+	const { locale } = await params;
+	if (!routing.locales.includes(locale)) {
+		notFound();
+	}
+
+	const lang = LANG_MAP[locale] || locale;
+	const messages = await getMessages();
+
+	return (
+		<html lang={lang} className={`${spaceGrotesk.variable} ${manrope.variable} ${jetbrainsMono.variable}`} suppressHydrationWarning>
+			<head>
+				{/* Dados estruturados do site e da organização. É o que permite ao
+				    Google montar o box de busca interna e entender a autoria. */}
+				<script
+					type="application/ld+json"
+					dangerouslySetInnerHTML={{ __html: JSON.stringify(jsonLd.siteESociedade()) }}
+				/>
+			</head>
+			<body className="font-sans antialiased bg-canvas text-ink overflow-x-clip" suppressHydrationWarning>
+				<a
+					href="#conteudo"
+					className="sr-only focus:not-sr-only focus:fixed focus:left-4 focus:top-4 focus:z-[200] focus:rounded-full focus:bg-ink focus:px-5 focus:py-3 focus:text-sm focus:font-semibold focus:text-canvas"
+				>
+					Pular para o conteúdo
+				</a>
+				<NextIntlClientProvider locale={locale} messages={messages}>
+					<Providers>
+						{children}
+					</Providers>
+				</NextIntlClientProvider>
+			</body>
+		</html>
+	);
+}