feat(header): add Download nav link → /account/desktop-install

Inserts a Download entry between Pricing and Blog in the main nav.
Routes to the existing DesktopInstallPage in the velxio-prod pro
overlay (auth gate + platform-detect + signed-licence download flow).

i18n: header.nav.download added across all 9 shipped locales
(en/es/ja/it/de/ru/pt-br/zh-cn/fr) with native translations.

Self-hosted OSS image: the route doesn't exist there, so the link
lands on the upstream router's 404 — same fallback behaviour as
/pricing already has for self-hosters. Acceptable until the OSS
side gets its own placeholder.

frontend/src/components/layout/AppHeader.tsx

@@ -142,6 +142,12 @@ export const AppHeader: React.FC<AppHeaderProps> = ({ autoSave }) => {
             <Link to={localize('/pricing')} className={'header-nav-link' + isActive('/pricing')}>
               {t('header.nav.pricing')}
             </Link>
+            <Link
+              to={localize('/account/desktop-install')}
+              className={'header-nav-link' + isActive('/account/desktop-install')}
+            >
+              {t('header.nav.download')}
+            </Link>
             <a
               href={blogUrlFor(currentLocale)}
               className="header-nav-link"

frontend/src/i18n/locales/de/common.json

@@ -10,6 +10,7 @@
       "editor": "Editor",
       "about": "Über uns",
       "pricing": "Preise",
+      "download": "Download",
       "blog": "Blog",
       "github": "GitHub",
       "discord": "Discord"
@@ -402,4 +403,4 @@
       }
     }
   }
-}
+}

frontend/src/i18n/locales/en/common.json

@@ -10,6 +10,7 @@
       "editor": "Editor",
       "about": "About",
       "pricing": "Pricing",
+      "download": "Download",
       "blog": "Blog",
       "github": "GitHub",
       "discord": "Discord"
@@ -402,4 +403,4 @@
       }
     }
   }
-}
+}

frontend/src/i18n/locales/es/common.json

@@ -10,6 +10,7 @@
       "editor": "Editor",
       "about": "Acerca de",
       "pricing": "Precios",
+      "download": "Descargar",
       "blog": "Blog",
       "github": "GitHub",
       "discord": "Discord"
@@ -402,4 +403,4 @@
       }
     }
   }
-}
+}

frontend/src/i18n/locales/fr/common.json

@@ -10,6 +10,7 @@
       "editor": "Éditeur",
       "about": "À propos",
       "pricing": "Tarifs",
+      "download": "Télécharger",
       "blog": "Blog",
       "github": "GitHub",
       "discord": "Discord"
@@ -402,4 +403,4 @@
       }
     }
   }
-}
+}

frontend/src/i18n/locales/it/common.json

@@ -10,6 +10,7 @@
       "editor": "Editor",
       "about": "Informazioni",
       "pricing": "Prezzi",
+      "download": "Scarica",
       "blog": "Blog",
       "github": "GitHub",
       "discord": "Discord"
@@ -402,4 +403,4 @@
       }
     }
   }
-}
+}

frontend/src/i18n/locales/ja/common.json

@@ -10,6 +10,7 @@
       "editor": "エディター",
       "about": "概要",
       "pricing": "料金",
+      "download": "ダウンロード",
       "blog": "ブログ",
       "github": "GitHub",
       "discord": "Discord"
@@ -402,4 +403,4 @@
       }
     }
   }
-}
+}

frontend/src/i18n/locales/pt-br/common.json

@@ -10,6 +10,7 @@
       "editor": "Editor",
       "about": "Sobre",
       "pricing": "Preços",
+      "download": "Baixar",
       "blog": "Blog",
       "github": "GitHub",
       "discord": "Discord"
@@ -402,4 +403,4 @@
       }
     }
   }
-}
+}

frontend/src/i18n/locales/ru/common.json

@@ -10,6 +10,7 @@
       "editor": "Редактор",
       "about": "О проекте",
       "pricing": "Цены",
+      "download": "Скачать",
       "blog": "Блог",
       "github": "GitHub",
       "discord": "Discord"
@@ -402,4 +403,4 @@
       }
     }
   }
-}
+}

frontend/src/i18n/locales/zh-cn/common.json

@@ -10,6 +10,7 @@
       "editor": "编辑器",
       "about": "关于",
       "pricing": "价格",
+      "download": "下载",
       "blog": "博客",
       "github": "GitHub",
       "discord": "Discord"
@@ -402,4 +403,4 @@
       }
     }
   }
-}
+}