Make the resume bilingual and part of the shared site chrome

Adds a Russian version (data/resume.ru.json, default language) with an RU/EN
switch stored under the key shared with the front page and the portfolio.
The top bar becomes the site-wide one (brand, Resume, Portfolio, Gitea,
Contact, language, theme) with a second row of anchors for this page's
sections, and the fonts move to Unbounded and Onest so the three pages share
one type system. Portfolio links now point at /portfolio/.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XtcZtnG4GQA1d6mW5PNrS9

components/ThemeToggle.tsx

@@ -1,6 +1,7 @@
 'use client'
 
 import { useEffect, useState } from 'react'
+import { useLang } from '@/lib/useLang'
 import styles from './topbar.module.css'
 
 type Theme = 'dark' | 'light'
@@ -8,6 +9,7 @@ type Theme = 'dark' | 'light'
 /** Switches between the dark (default) and light theme; the choice is remembered in this browser. */
 export default function ThemeToggle() {
   const [theme, setTheme] = useState<Theme>('dark')
+  const lang = useLang()
 
   // The page starts dark; a small script in <head> applies a stored "light" choice before the first paint.
   useEffect(() => {
@@ -30,7 +32,11 @@ export default function ThemeToggle() {
       type="button"
       className={styles.toggle}
       onClick={toggle}
-      aria-label={theme === 'dark' ? 'Switch to the light theme' : 'Switch to the dark theme'}
+      aria-label={
+        theme === 'dark'
+          ? lang === 'ru' ? 'Включить светлую тему' : 'Switch to the light theme'
+          : lang === 'ru' ? 'Включить тёмную тему' : 'Switch to the dark theme'
+      }
     >
       {theme === 'dark' ? (
         <svg viewBox="0 0 24 24" aria-hidden="true">