feat: add filtering to all entity list pages

- Tracking configs: filter by name + provider type
- Template configs: filter by name + provider type
- Command configs: filter by name + provider type
- Notification trackers: filter by name + provider
- Command trackers: filter by name + provider
- Targets: filter by name (type filtering already existed)
- Nav badge counts include system-owned entities (user_id=0)
- Shows "no items match filter" vs "no items yet" empty states

frontend/src/lib/i18n/en.json

@@ -748,7 +748,11 @@
 		"syntaxError": "Syntax error",
 		"undefinedVar": "Unknown variable",
 		"line": "line",
-		"add": "Add"
+		"add": "Add",
+		"filterByName": "Filter by name...",
+		"allTypes": "All types",
+		"allProviders": "All providers",
+		"noFilterResults": "No items match the current filter."
 	},
 	"error": {
 		"notFound": "Page not found",

frontend/src/lib/i18n/ru.json

@@ -748,7 +748,11 @@
 		"syntaxError": "Ошибка синтаксиса",
 		"undefinedVar": "Неизвестная переменная",
 		"line": "строка",
-		"add": "Добавить"
+		"add": "Добавить",
+		"filterByName": "Фильтр по имени...",
+		"allTypes": "Все типы",
+		"allProviders": "Все провайдеры",
+		"noFilterResults": "Нет элементов, соответствующих фильтру."
 	},
 	"error": {
 		"notFound": "Страница не найдена",