feat(phase3): import/export, sparklines, user theme overrides

- JSON import/export with conflict resolution (skip/overwrite) + admin UI
- Ping history sparklines on AppWidget and AppCard (24h, 288 points)
- Hourly cleanup job for old AppStatus records
- User theme preferences (hue, saturation, mode, background, locale)
- Settings page with ThemeCustomizer (sliders, toggles, live preview)
- Prisma migration for user preference fields
- i18n translations for all new strings (EN/RU)

src/lib/i18n/en.json

@@ -127,6 +127,8 @@
   "app.healthcheck_timeout": "Timeout (ms)",
   "app.healthcheck_interval": "Interval (seconds)",
   "app.icon_board_label": "Icon (Lucide name)",
+  "app.uptime": "uptime",
+  "app.history_loading": "Loading history...",
 
   "admin.panel": "Admin Panel",
   "admin.users": "Users",
@@ -213,6 +215,23 @@
   "admin.perm_none": "No permissions configured.",
   "admin.perm_search_placeholder": "Type to search...",
 
+  "admin.import_export_title": "Import / Export",
+  "admin.import_export_description": "Export all data (apps, boards, groups, settings) as JSON, or import from a previously exported file.",
+  "admin.export_section": "Export Data",
+  "admin.export_button": "Export JSON",
+  "admin.export_exporting": "Exporting...",
+  "admin.export_success": "Export downloaded successfully.",
+  "admin.import_section": "Import Data",
+  "admin.import_select_file": "Select a JSON export file",
+  "admin.import_preview": "Preview",
+  "admin.import_mode_label": "Conflict Resolution",
+  "admin.import_mode_skip": "Skip existing (keep current data)",
+  "admin.import_mode_overwrite": "Overwrite existing (replace with imported data)",
+  "admin.import_button": "Import",
+  "admin.import_importing": "Importing...",
+  "admin.import_success": "Import completed.",
+  "admin.import_invalid_json": "Selected file is not valid JSON.",
+
   "search.placeholder": "Search apps and boards...",
   "search.trigger": "Search...",
   "search.min_chars": "Type at least 2 characters to search",
@@ -261,5 +280,16 @@
   "home.view_boards": "View Boards",
   "home.browse_apps": "Browse Apps",
 
-  "language.label": "Language"
+  "language.label": "Language",
+
+  "settings.title": "Settings",
+  "settings.theme": "Theme Mode",
+  "settings.primary_color": "Primary Color",
+  "settings.hue": "Hue",
+  "settings.saturation": "Saturation",
+  "settings.background": "Background Effect",
+  "settings.language": "Language",
+  "settings.save": "Save Preferences",
+  "settings.saving": "Saving...",
+  "settings.saved": "Preferences saved!"
 }

src/lib/i18n/ru.json

@@ -127,6 +127,8 @@
   "app.healthcheck_timeout": "\u0422\u0430\u0439\u043c\u0430\u0443\u0442 (\u043c\u0441)",
   "app.healthcheck_interval": "\u0418\u043d\u0442\u0435\u0440\u0432\u0430\u043b (\u0441\u0435\u043a\u0443\u043d\u0434\u044b)",
   "app.icon_board_label": "\u0418\u043a\u043e\u043d\u043a\u0430 (Lucide)",
+  "app.uptime": "\u0430\u043f\u0442\u0430\u0439\u043c",
+  "app.history_loading": "\u0417\u0430\u0433\u0440\u0443\u0437\u043a\u0430 \u0438\u0441\u0442\u043e\u0440\u0438\u0438...",
 
   "admin.panel": "\u041f\u0430\u043d\u0435\u043b\u044c \u0430\u0434\u043c\u0438\u043d\u0438\u0441\u0442\u0440\u0430\u0442\u043e\u0440\u0430",
   "admin.users": "\u041f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u0438",
@@ -213,7 +215,24 @@
   "admin.perm_none": "\u041f\u0440\u0430\u0432\u0430 \u043d\u0435 \u043d\u0430\u0441\u0442\u0440\u043e\u0435\u043d\u044b.",
   "admin.perm_search_placeholder": "\u041d\u0430\u0447\u043d\u0438\u0442\u0435 \u0432\u0432\u043e\u0434\u0438\u0442\u044c...",
 
-  "search.placeholder": "\u041f\u043e\u0438\u0441\u043a \u043f\u0440\u0438\u043b\u043e\u0436\u0435\u043d\u0438\u0439 \u0438 \u0434\u043e\u0441\u043e\u043a...",
+  "admin.import_export_title": "Импорт / Экспорт",
+  "admin.import_export_description": "Экспортируйте все данные (приложения, доски, группы, настройки) в формате JSON или импортируйте из ранее экспортированного файла.",
+  "admin.export_section": "Экспорт данных",
+  "admin.export_button": "Экспорт JSON",
+  "admin.export_exporting": "Экспорт...",
+  "admin.export_success": "Экспорт успешно скачан.",
+  "admin.import_section": "Импорт данных",
+  "admin.import_select_file": "Выберите JSON-файл экспорта",
+  "admin.import_preview": "Предпросмотр",
+  "admin.import_mode_label": "Разрешение конфликтов",
+  "admin.import_mode_skip": "Пропустить существующие (оставить текущие данные)",
+  "admin.import_mode_overwrite": "Перезаписать существующие (заменить импортированными)",
+  "admin.import_button": "Импортировать",
+  "admin.import_importing": "Импорт...",
+  "admin.import_success": "Импорт завершён.",
+  "admin.import_invalid_json": "Выбранный файл не является корректным JSON.",
+
+  "search.placeholder": "Поиск приложений и досок...",
   "search.trigger": "\u041f\u043e\u0438\u0441\u043a...",
   "search.min_chars": "\u0412\u0432\u0435\u0434\u0438\u0442\u0435 \u043c\u0438\u043d\u0438\u043c\u0443\u043c 2 \u0441\u0438\u043c\u0432\u043e\u043b\u0430 \u0434\u043b\u044f \u043f\u043e\u0438\u0441\u043a\u0430",
   "search.no_results": "\u041d\u0438\u0447\u0435\u0433\u043e \u043d\u0435 \u043d\u0430\u0439\u0434\u0435\u043d\u043e \u043f\u043e \u0437\u0430\u043f\u0440\u043e\u0441\u0443 \u00ab{query}\u00bb",
@@ -261,5 +280,16 @@
   "home.view_boards": "\u041f\u043e\u0441\u043c\u043e\u0442\u0440\u0435\u0442\u044c \u0434\u043e\u0441\u043a\u0438",
   "home.browse_apps": "\u041e\u0431\u0437\u043e\u0440 \u043f\u0440\u0438\u043b\u043e\u0436\u0435\u043d\u0438\u0439",
 
-  "language.label": "\u042f\u0437\u044b\u043a"
+  "language.label": "\u042f\u0437\u044b\u043a",
+
+  "settings.title": "\u041d\u0430\u0441\u0442\u0440\u043e\u0439\u043a\u0438",
+  "settings.theme": "\u0420\u0435\u0436\u0438\u043c \u0442\u0435\u043c\u044b",
+  "settings.primary_color": "\u041e\u0441\u043d\u043e\u0432\u043d\u043e\u0439 \u0446\u0432\u0435\u0442",
+  "settings.hue": "\u041e\u0442\u0442\u0435\u043d\u043e\u043a",
+  "settings.saturation": "\u041d\u0430\u0441\u044b\u0449\u0435\u043d\u043d\u043e\u0441\u0442\u044c",
+  "settings.background": "\u042d\u0444\u0444\u0435\u043a\u0442 \u0444\u043e\u043d\u0430",
+  "settings.language": "\u042f\u0437\u044b\u043a",
+  "settings.save": "\u0421\u043e\u0445\u0440\u0430\u043d\u0438\u0442\u044c \u043d\u0430\u0441\u0442\u0440\u043e\u0439\u043a\u0438",
+  "settings.saving": "\u0421\u043e\u0445\u0440\u0430\u043d\u0435\u043d\u0438\u0435...",
+  "settings.saved": "\u041d\u0430\u0441\u0442\u0440\u043e\u0439\u043a\u0438 \u0441\u043e\u0445\u0440\u0430\u043d\u0435\u043d\u044b!"
 }