docs: add localized documentation pages

Adds translated docs for Spanish, Korean, Polish, Portuguese, Ukrainian, and Chinese
Covers install, quickstart, themes, troubleshooting, tunnels, and reverse proxy guides
Updates docs workflow, sidebar, and contributor documentation

packages/docs/sidebar.config.json

@@ -2,24 +2,125 @@
   "sections": [
     {
       "label": "Start here",
+      "translations": {
+        "uk": "Почніть тут",
+        "zh-CN": "从这里开始",
+        "es": "Empieza aquí",
+        "pt-BR": "Comece aqui",
+        "ko": "여기서 시작",
+        "pl": "Zacznij tutaj"
+      },
       "items": [
-        { "label": "Overview", "link": "/" },
-        { "label": "Install", "link": "/install/" },
-        { "label": "Quickstart", "link": "/quickstart/" },
-        { "label": "Tunnels", "link": "/tunnels/" }
+        {
+          "label": "Overview",
+          "link": "/",
+          "translations": {
+            "uk": "Огляд",
+            "zh-CN": "概览",
+            "es": "Visión general",
+            "pt-BR": "Visão geral",
+            "ko": "개요",
+            "pl": "Przegląd"
+          }
+        },
+        {
+          "label": "Install",
+          "link": "/install/",
+          "translations": {
+            "uk": "Встановлення",
+            "zh-CN": "安装",
+            "es": "Instalación",
+            "pt-BR": "Instalação",
+            "ko": "설치",
+            "pl": "Instalacja"
+          }
+        },
+        {
+          "label": "Quickstart",
+          "link": "/quickstart/",
+          "translations": {
+            "uk": "Швидкий старт",
+            "zh-CN": "快速开始",
+            "es": "Inicio rápido",
+            "pt-BR": "Início rápido",
+            "ko": "빠른 시작",
+            "pl": "Szybki start"
+          }
+        },
+        {
+          "label": "Tunnels",
+          "link": "/tunnels/",
+          "translations": {
+            "uk": "Тунелі",
+            "zh-CN": "隧道",
+            "es": "Túneles",
+            "pt-BR": "Túneis",
+            "ko": "터널",
+            "pl": "Tunele"
+          }
+        }
       ]
     },
     {
       "label": "Customize",
+      "translations": {
+        "uk": "Налаштування",
+        "zh-CN": "自定义",
+        "es": "Personalizar",
+        "pt-BR": "Personalizar",
+        "ko": "맞춤 설정",
+        "pl": "Dostosuj"
+      },
       "items": [
-        { "label": "Themes", "link": "/themes/" }
+        {
+          "label": "Themes",
+          "link": "/themes/",
+          "translations": {
+            "uk": "Теми",
+            "zh-CN": "主题",
+            "es": "Temas",
+            "pt-BR": "Temas",
+            "ko": "테마",
+            "pl": "Motywy"
+          }
+        }
       ]
     },
     {
       "label": "Help",
+      "translations": {
+        "uk": "Допомога",
+        "zh-CN": "帮助",
+        "es": "Ayuda",
+        "pt-BR": "Ajuda",
+        "ko": "도움말",
+        "pl": "Pomoc"
+      },
       "items": [
-        { "label": "Reverse Proxy", "link": "/reverse-proxy/" },
-        { "label": "Troubleshooting", "link": "/troubleshooting/" }
+        {
+          "label": "Reverse Proxy",
+          "link": "/reverse-proxy/",
+          "translations": {
+            "uk": "Зворотний проксі",
+            "zh-CN": "反向代理",
+            "es": "Proxy inverso",
+            "pt-BR": "Proxy reverso",
+            "ko": "리버스 프록시",
+            "pl": "Reverse proxy"
+          }
+        },
+        {
+          "label": "Troubleshooting",
+          "link": "/troubleshooting/",
+          "translations": {
+            "uk": "Усунення несправностей",
+            "zh-CN": "问题排查",
+            "es": "Resolución de problemas",
+            "pt-BR": "Solução de problemas",
+            "ko": "문제 해결",
+            "pl": "Rozwiązywanie problemów"
+          }
+        }
       ]
     }
   ]