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

web/src/i18n/locales/zh-CN.json

@@ -1605,6 +1605,14 @@
     "添加键值对": "添加键值对",
     "添加问答": "添加问答",
     "添加额度": "添加额度",
+    "减少": "减少",
+    "覆盖": "覆盖",
+    "调整额度": "调整额度",
+    "调整额度成功": "调整额度成功",
+    "当前额度": "当前额度",
+    "变更": "变更",
+    "预计结果": "预计结果",
+    "正数为增加，负数为减少": "正数为增加，负数为减少",
     "清理方式": "清理方式",
     "清理日志文件": "清理日志文件",
     "清空": "清空",
@@ -2737,6 +2745,8 @@
     "请输入总额度": "请输入总额度",
     "0 表示不限": "0 表示不限",
     "原生额度": "原生额度",
+    "使用原生额度输入": "使用原生额度输入",
+    "收起原生额度输入": "收起原生额度输入",
     "升级分组": "升级分组",
     "不升级": "不升级",
     "购买或手动新增订阅会升级到该分组；当套餐失效/过期或手动作废/删除后，将回退到升级前分组。回退不会立即生效，通常会有几分钟延迟。": "购买或手动新增订阅会升级到该分组；当套餐失效/过期或手动作废/删除后，将回退到升级前分组。回退不会立即生效，通常会有几分钟延迟。",