feat: /subscribe pricing page + Pro nav link + fix checkout token scope

- Add /subscribe route with hero, benefits list, and pricing cards
  (annual featured with Save 33% badge, monthly secondary)
- Add 'Pro' link in nav for non-Pro users
- Add 'See plans' link in profile subscription section
- i18n keys across en/fr/id/pt/ru for all subscribe strings

Note: checkout still requires POLAR_API_TOKEN with checkouts:write scope.
Regenerate the token at polar.sh to fix the 502 error on subscribe buttons.

ui/messages/en.json

@@ -366,6 +366,26 @@
   "profile_upgrade_monthly": "Monthly \u2014 $6 / mo",
   "profile_upgrade_annual": "Annual \u2014 $48 / yr",
   "profile_free_limits": "Free plan: 3 audio chapters per day, English reading only.",
+  "subscribe_page_title": "Go Pro \u2014 libnovel",
+  "subscribe_heading": "Read more. Listen more.",
+  "subscribe_subheading": "Upgrade to Pro and unlock the full libnovel experience.",
+  "subscribe_monthly_label": "Monthly",
+  "subscribe_monthly_price": "$6",
+  "subscribe_monthly_period": "per month",
+  "subscribe_annual_label": "Annual",
+  "subscribe_annual_price": "$48",
+  "subscribe_annual_period": "per year",
+  "subscribe_annual_save": "Save 33%",
+  "subscribe_cta_monthly": "Start monthly plan",
+  "subscribe_cta_annual": "Start annual plan",
+  "subscribe_already_pro": "You already have a Pro subscription.",
+  "subscribe_manage": "Manage subscription",
+  "subscribe_benefit_audio": "Unlimited audio chapters per day",
+  "subscribe_benefit_voices": "Voice selection across all TTS engines",
+  "subscribe_benefit_translation": "Read in French, Indonesian, Portuguese, and Russian",
+  "subscribe_benefit_downloads": "Download chapters for offline listening",
+  "subscribe_login_prompt": "Sign in to subscribe",
+  "subscribe_login_cta": "Sign in",
 
   "user_currently_reading": "Currently Reading",
   "user_library_count": "Library ({n})",

ui/messages/fr.json

@@ -366,6 +366,26 @@
   "profile_upgrade_monthly": "Mensuel — 6 $ / mois",
   "profile_upgrade_annual": "Annuel — 48 $ / an",
   "profile_free_limits": "Plan gratuit : 3 chapitres audio par jour, lecture en anglais uniquement.",
+  "subscribe_page_title": "Passer Pro \u2014 libnovel",
+  "subscribe_heading": "Lisez plus. Écoutez plus.",
+  "subscribe_subheading": "Passez Pro et débloquez l'expérience libnovel complète.",
+  "subscribe_monthly_label": "Mensuel",
+  "subscribe_monthly_price": "6 $",
+  "subscribe_monthly_period": "par mois",
+  "subscribe_annual_label": "Annuel",
+  "subscribe_annual_price": "48 $",
+  "subscribe_annual_period": "par an",
+  "subscribe_annual_save": "Économisez 33 %",
+  "subscribe_cta_monthly": "Commencer le plan mensuel",
+  "subscribe_cta_annual": "Commencer le plan annuel",
+  "subscribe_already_pro": "Vous avez déjà un abonnement Pro.",
+  "subscribe_manage": "Gérer l'abonnement",
+  "subscribe_benefit_audio": "Chapitres audio illimités par jour",
+  "subscribe_benefit_voices": "Sélection de voix pour tous les moteurs TTS",
+  "subscribe_benefit_translation": "Lire en français, indonésien, portugais et russe",
+  "subscribe_benefit_downloads": "Télécharger des chapitres pour une écoute hors ligne",
+  "subscribe_login_prompt": "Connectez-vous pour vous abonner",
+  "subscribe_login_cta": "Se connecter",
 
   "user_currently_reading": "En cours de lecture",
   "user_library_count": "Bibliothèque ({n})",

ui/messages/id.json

@@ -366,6 +366,26 @@
   "profile_upgrade_monthly": "Bulanan — $6 / bln",
   "profile_upgrade_annual": "Tahunan — $48 / thn",
   "profile_free_limits": "Paket gratis: 3 bab audio per hari, hanya bahasa Inggris.",
+  "subscribe_page_title": "Jadi Pro \u2014 libnovel",
+  "subscribe_heading": "Baca lebih. Dengarkan lebih.",
+  "subscribe_subheading": "Tingkatkan ke Pro dan buka pengalaman libnovel sepenuhnya.",
+  "subscribe_monthly_label": "Bulanan",
+  "subscribe_monthly_price": "$6",
+  "subscribe_monthly_period": "per bulan",
+  "subscribe_annual_label": "Tahunan",
+  "subscribe_annual_price": "$48",
+  "subscribe_annual_period": "per tahun",
+  "subscribe_annual_save": "Hemat 33%",
+  "subscribe_cta_monthly": "Mulai paket bulanan",
+  "subscribe_cta_annual": "Mulai paket tahunan",
+  "subscribe_already_pro": "Anda sudah berlangganan Pro.",
+  "subscribe_manage": "Kelola langganan",
+  "subscribe_benefit_audio": "Bab audio tak terbatas per hari",
+  "subscribe_benefit_voices": "Pilihan suara untuk semua mesin TTS",
+  "subscribe_benefit_translation": "Baca dalam bahasa Prancis, Indonesia, Portugis, dan Rusia",
+  "subscribe_benefit_downloads": "Unduh bab untuk didengarkan secara offline",
+  "subscribe_login_prompt": "Masuk untuk berlangganan",
+  "subscribe_login_cta": "Masuk",
 
   "user_currently_reading": "Sedang Dibaca",
   "user_library_count": "Perpustakaan ({n})",

ui/messages/pt.json

@@ -366,6 +366,26 @@
   "profile_upgrade_monthly": "Mensal — $6 / mês",
   "profile_upgrade_annual": "Anual — $48 / ano",
   "profile_free_limits": "Plano gratuito: 3 capítulos de áudio por dia, somente inglês.",
+  "subscribe_page_title": "Seja Pro \u2014 libnovel",
+  "subscribe_heading": "Leia mais. Ouça mais.",
+  "subscribe_subheading": "Torne-se Pro e desbloqueie a experiência completa do libnovel.",
+  "subscribe_monthly_label": "Mensal",
+  "subscribe_monthly_price": "$6",
+  "subscribe_monthly_period": "por mês",
+  "subscribe_annual_label": "Anual",
+  "subscribe_annual_price": "$48",
+  "subscribe_annual_period": "por ano",
+  "subscribe_annual_save": "Economize 33%",
+  "subscribe_cta_monthly": "Começar plano mensal",
+  "subscribe_cta_annual": "Começar plano anual",
+  "subscribe_already_pro": "Você já tem uma assinatura Pro.",
+  "subscribe_manage": "Gerenciar assinatura",
+  "subscribe_benefit_audio": "Capítulos de áudio ilimitados por dia",
+  "subscribe_benefit_voices": "Seleção de voz para todos os mecanismos TTS",
+  "subscribe_benefit_translation": "Leia em francês, indonésio, português e russo",
+  "subscribe_benefit_downloads": "Baixe capítulos para ouvir offline",
+  "subscribe_login_prompt": "Entre para assinar",
+  "subscribe_login_cta": "Entrar",
 
   "user_currently_reading": "Lendo Agora",
   "user_library_count": "Biblioteca ({n})",

ui/messages/ru.json

@@ -366,6 +366,26 @@
   "profile_upgrade_monthly": "Ежемесячно — $6 / мес",
   "profile_upgrade_annual": "Ежегодно — $48 / год",
   "profile_free_limits": "Бесплатный план: 3 аудиоглавы в день, только английский.",
+  "subscribe_page_title": "Перейти на Pro \u2014 libnovel",
+  "subscribe_heading": "Читайте больше. Слушайте больше.",
+  "subscribe_subheading": "Перейдите на Pro и откройте полный опыт libnovel.",
+  "subscribe_monthly_label": "Ежемесячно",
+  "subscribe_monthly_price": "$6",
+  "subscribe_monthly_period": "в месяц",
+  "subscribe_annual_label": "Ежегодно",
+  "subscribe_annual_price": "$48",
+  "subscribe_annual_period": "в год",
+  "subscribe_annual_save": "Сэкономьте 33%",
+  "subscribe_cta_monthly": "Начать месячный план",
+  "subscribe_cta_annual": "Начать годовой план",
+  "subscribe_already_pro": "У вас уже есть подписка Pro.",
+  "subscribe_manage": "Управление подпиской",
+  "subscribe_benefit_audio": "Неограниченные аудиоглавы в день",
+  "subscribe_benefit_voices": "Выбор голоса для всех TTS-движков",
+  "subscribe_benefit_translation": "Читайте на французском, индонезийском, португальском и русском",
+  "subscribe_benefit_downloads": "Скачивайте главы для прослушивания офлайн",
+  "subscribe_login_prompt": "Войдите, чтобы оформить подписку",
+  "subscribe_login_cta": "Войти",
 
   "user_currently_reading": "Сейчас читает",
   "user_library_count": "Библиотека ({n})",