i18n(ru): complete and improve Russian localization (2dust#9021)

Translate 9 previously untranslated strings and improve 104 existing
translations in ResUI.ru.resx for accuracy, consistency and
naturalness.

New translations:
- TbCustomDnsRay, TbCustomDnsSingbox — custom DNS labels
- TbIcmpRoutingPolicy, TbInsecureConcurrency, TbLegacyProtect, TbUot
- TbUsername, menuEditFormat, menuEditPaste

Key improvements:
- Unify "перезагрузка" → "перезапуск" for app restart context
- Fix grammar: missing spaces before parentheses, hyphen in
  "по умолчанию", capitalization
- Restore lost parts of original strings (Enter hint, restart notes,
  process in auto-sort list)
- Fix incorrect translations: "системные узлы" → "системный файл
  hosts", "PublicKey" → "Открытый ключ", "Режим VPN" → "Включить TUN"
- Improve naturalness: "Обнулить" → "Сбросить", "Просмотр" → "Обзор",
  "Содействие" → "Продвижение"
- Align checkbox labels to infinitive form per Russian UI conventions
- Standardize terminology across all proxy, routing, DNS settings

15 universal technical abbreviations (LAN, UUID, MTU, TLS, ALPN, SNI,
FakeIP, Bootstrap DNS, etc.) intentionally kept as-is.

Author: aleksandr-miheichev