feat(ui): language persistence, theme fix, font/size settings, header quick-access

- Fix language not persisting after refresh: save locale in user_settings,
  set PARAGLIDE_LOCALE cookie from DB preference on server load
- Fix theme change not applying: context setter was mismatched (setTheme vs current)
- Add font family (system/serif/mono) and text size (sm/md/lg/xl) user settings
  stored in DB and applied via CSS custom properties
- Add theme color dots and language picker to desktop header for quick access
- Footer locale switcher now saves preference to DB before switching
- Remove change password section (OAuth-only, no password login)
- Fix active sessions piling up: reuse existing session on re-login via OAuth
- Extend speed step cycle to include 2.5× and 3.0× (matching profile slider)
- Replace plain checkbox with modern toggle switch for auto-next setting
- Fix catalogue status labels (ongoing/completed) to use translation keys
- Add font family and text size translation keys to all 5 locale files

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/messages/en.json

@@ -392,5 +392,15 @@
   "reader_generate_samples": "Generate missing samples",
   "reader_voice_applies_next": "New voice applies on next \u201cPlay narration\u201d.",
   "reader_choose_voice": "Choose Voice",
-  "reader_generating_narration": "Generating narration\u2026"
+  "reader_generating_narration": "Generating narration\u2026",
+
+  "profile_font_family": "Font Family",
+  "profile_font_system": "System",
+  "profile_font_serif": "Serif",
+  "profile_font_mono": "Monospace",
+  "profile_text_size": "Text Size",
+  "profile_text_size_sm": "Small",
+  "profile_text_size_md": "Normal",
+  "profile_text_size_lg": "Large",
+  "profile_text_size_xl": "X-Large"
 }

ui/messages/fr.json

@@ -391,5 +391,15 @@
   "reader_generate_samples": "Générer les échantillons manquants",
   "reader_voice_applies_next": "La nouvelle voix s'appliquera au prochain « Lire la narration ».",
   "reader_choose_voice": "Choisir une voix",
-  "reader_generating_narration": "Génération de la narration…"
+  "reader_generating_narration": "Génération de la narration…",
+
+  "profile_font_family": "Police",
+  "profile_font_system": "Système",
+  "profile_font_serif": "Serif",
+  "profile_font_mono": "Mono",
+  "profile_text_size": "Taille du texte",
+  "profile_text_size_sm": "Petit",
+  "profile_text_size_md": "Normal",
+  "profile_text_size_lg": "Grand",
+  "profile_text_size_xl": "Très grand"
 }

ui/messages/id.json

@@ -391,5 +391,15 @@
   "reader_generate_samples": "Hasilkan sampel yang hilang",
   "reader_voice_applies_next": "Suara baru berlaku pada \"Putar narasi\" berikutnya.",
   "reader_choose_voice": "Pilih Suara",
-  "reader_generating_narration": "Membuat narasi…"
+  "reader_generating_narration": "Membuat narasi…",
+
+  "profile_font_family": "Jenis Font",
+  "profile_font_system": "Sistem",
+  "profile_font_serif": "Serif",
+  "profile_font_mono": "Mono",
+  "profile_text_size": "Ukuran Teks",
+  "profile_text_size_sm": "Kecil",
+  "profile_text_size_md": "Normal",
+  "profile_text_size_lg": "Besar",
+  "profile_text_size_xl": "Sangat Besar"
 }

ui/messages/pt-BR.json

@@ -391,5 +391,15 @@
   "reader_generate_samples": "Gerar amostras ausentes",
   "reader_voice_applies_next": "A nova voz será aplicada no próximo \"Reproduzir narração\".",
   "reader_choose_voice": "Escolher Voz",
-  "reader_generating_narration": "Gerando narração…"
+  "reader_generating_narration": "Gerando narração…",
+
+  "profile_font_family": "Fonte",
+  "profile_font_system": "Sistema",
+  "profile_font_serif": "Serif",
+  "profile_font_mono": "Mono",
+  "profile_text_size": "Tamanho do texto",
+  "profile_text_size_sm": "Pequeno",
+  "profile_text_size_md": "Normal",
+  "profile_text_size_lg": "Grande",
+  "profile_text_size_xl": "Muito grande"
 }

ui/messages/ru.json

@@ -391,5 +391,15 @@
   "reader_generate_samples": "Сгенерировать недостающие образцы",
   "reader_voice_applies_next": "Новый голос применится при следующем нажатии «Воспроизвести».",
   "reader_choose_voice": "Выбрать голос",
-  "reader_generating_narration": "Генерация озвучки…"
+  "reader_generating_narration": "Генерация озвучки…",
+
+  "profile_font_family": "Шрифт",
+  "profile_font_system": "Системный",
+  "profile_font_serif": "Serif",
+  "profile_font_mono": "Моноширинный",
+  "profile_text_size": "Размер текста",
+  "profile_text_size_sm": "Маленький",
+  "profile_text_size_md": "Нормальный",
+  "profile_text_size_lg": "Большой",
+  "profile_text_size_xl": "Очень большой"
 }