feat: add Russian localization and independent STT languages

app/layout.tsx

@@ -1,5 +1,9 @@
+import { headers } from "next/headers";
+import { readSettingsRecord } from "@/src/server";
+import { resolveLanguage, systemLanguage, translate } from "@/src/core";
+import { I18nProvider } from "@/components/i18n";
 import type { Metadata } from "next";
-import { JetBrains_Mono, Source_Sans_3 } from "next/font/google";
+import { JetBrains_Mono, Source_Sans_3, Noto_Sans } from "next/font/google";
 import "katex/dist/katex.min.css";
 import "./globals.css";
 import { AppShell, SidebarProvider } from "@/components/sidebar";
@@ -10,21 +14,29 @@ import UpdateBanner from "@/components/update-banner";
 
 // Chrome = JetBrains Mono, teaching prose = Source Sans 3, titles = CMU
 // Serif (the bundled lh-cmu @font-face in globals.css — no CDN).
-const ui = JetBrains_Mono({ subsets: ["latin"], variable: "--font-jetbrains" });
+const ui = JetBrains_Mono({ subsets: ["latin", "cyrillic"], variable: "--font-jetbrains" });
 const prose = Source_Sans_3({ subsets: ["latin"], variable: "--font-sans3" });
 
-export const metadata: Metadata = {
-	title: "Learning Harness",
-	description: "A teacher agent with a memory — sessions, quizzes, and a knowledge graph of what you know.",
-};
+const russianProse = Noto_Sans({ subsets: ["latin", "cyrillic"], variable: "--font-russian-prose" });
 
-export default function RootLayout({ children }: { children: React.ReactNode }) {
+export async function generateMetadata(): Promise<Metadata> {
+	const language = resolveLanguage(readSettingsRecord()?.general?.language, (await headers()).get("accept-language"));
+	return {
+	title: "Learning Harness",
+	description: translate(language, "A teacher agent with a memory — sessions, quizzes, and a knowledge graph of what you know."),
+	};
+}
+
+export default async function RootLayout({ children }: { children: React.ReactNode }) {
+	const general = readSettingsRecord()?.general ?? {};
+	const system = systemLanguage((await headers()).get("accept-language"));
+	const language = resolveLanguage(general.language, system);
 	return (
-		<html lang="en" className={`dark ${ui.variable} ${prose.variable}`}>
+		<html lang={language} className={`dark ${ui.variable} ${prose.variable} ${russianProse.variable}`}>
 			<body className="min-h-dvh antialiased">
 			{/* The notification channel rides OUTSIDE everything: sidebar, dock,
 				 and pages all subscribe as the polls retire (push S3, 2026-10-02). */}
-			<ServerEventsProvider>
+			<I18nProvider initialGeneral={general} system={system}><ServerEventsProvider>
 				<AppearanceProvider>
 					<SidebarProvider>
 						<ActivityProvider>
@@ -35,6 +47,7 @@ export default function RootLayout({ children }: { children: React.ReactNode })
 			</ServerEventsProvider>
 			{/* Auto-update banner (Wave C): fixed card, Electron-only pushes. */}
 			<UpdateBanner />
+		</I18nProvider>
 		</body>
 		</html>
 	);