feat: replace quota input with amount-first UI and atomic quota adjustment

- Refactor token, redemption, and user quota inputs to prioritize monetary
  amount entry, with raw quota input collapsed by default
- Add atomic quota adjustment modal for users with add/subtract/override modes,
  bypassing batch update queue for immediate DB consistency
- Make user quota fields readonly in edit form; all modifications go through
  the dedicated adjust-quota modal via POST /api/user/manage
- Add DecreaseUserQuota `db` parameter for direct DB writes, matching
  IncreaseUserQuota behavior
- Support negative quota display in amount conversion helpers
- Add i18n keys for all new UI strings across all locales

i18n/locales/en.yaml

@@ -91,6 +91,7 @@ user.wechat_id_empty: "WeChat ID is empty!"
 user.telegram_id_empty: "Telegram ID is empty!"
 user.telegram_not_bound: "This Telegram account is not bound"
 user.linux_do_id_empty: "Linux DO ID is empty!"
+user.quota_change_zero: "Quota change amount cannot be zero"
 
 # Quota messages
 quota.negative: "Quota cannot be negative!"