💱 feat(settings): introduce site-wide quota display type (USD/CNY/TOKENS/CUSTOM)

Replace the legacy boolean “DisplayInCurrencyEnabled” with an injected, type-safe
configuration `general_setting.quota_display_type`, and wire it through the
backend and frontend.

Backend
- Add `QuotaDisplayType` to `operation_setting.GeneralSetting` with injected
  registration via `config.GlobalConfig.Register("general_setting", ...)`.
  Helpers: `IsCurrencyDisplay()`, `IsCNYDisplay()`, `GetQuotaDisplayType()`.
- Expose `quota_display_type` in `/api/status` and keep legacy
  `display_in_currency` for backward compatibility.
- Logger: update `LogQuota` and `FormatQuota` to support USD/CNY/TOKENS. When
  CNY is selected, convert using `operation_setting.USDExchangeRate`.
- Controllers:
  - `billing`: compute subscription/usage amounts based on the selected type
    (USD: divide by `QuotaPerUnit`; CNY: USD→CNY; TOKENS: keep raw tokens).
  - `topup` / `topup_stripe`: treat inputs as “amount” for USD/CNY and as
    token-count for TOKENS; adjust min topup and pay money accordingly.
  - `misc`: include `quota_display_type` in status payload.
- Compatibility: in `model/option.UpdateOption`, map updates to
  `DisplayInCurrencyEnabled` → `general_setting.quota_display_type`
  (true→USD, false→TOKENS). Keep exporting the legacy key in `OptionMap`.

Frontend
- Settings: replace the “display in currency” switch with a Select
  (`general_setting.quota_display_type`) offering USD / CNY / Tokens.
  Provide fallback mapping from legacy `DisplayInCurrencyEnabled`.
- Persist `quota_display_type` to localStorage (keep `display_in_currency`
  for legacy components).
- Rendering helpers: base all quota/price rendering on `quota_display_type`;
  use `usd_exchange_rate` for CNY symbol/values.
- Pricing page: default view currency follows site display type (USD/CNY),
  while TOKENS mode still allows per-view currency toggling when needed.

Notes
- No database migrations required.
- Legacy clients remain functional via compatibility fields.

web/src/helpers/render.jsx

@@ -830,12 +830,25 @@ export function renderQuotaNumberWithDigit(num, digits = 2) {
   if (typeof num !== 'number' || isNaN(num)) {
     return 0;
   }
-  let displayInCurrency = localStorage.getItem('display_in_currency');
+  const quotaDisplayType = localStorage.getItem('quota_display_type') || 'USD';
   num = num.toFixed(digits);
-  if (displayInCurrency) {
+  if (quotaDisplayType === 'CNY') {
+    return '¥' + num;
+  } else if (quotaDisplayType === 'USD') {
     return '$' + num;
+  } else if (quotaDisplayType === 'CUSTOM') {
+    const statusStr = localStorage.getItem('status');
+    let symbol = '¤';
+    try {
+      if (statusStr) {
+        const s = JSON.parse(statusStr);
+        symbol = s?.custom_currency_symbol || symbol;
+      }
+    } catch (e) {}
+    return symbol + num;
+  } else {
+    return num;
   }
-  return num;
 }
 
 export function renderNumberWithPoint(num) {
@@ -887,33 +900,67 @@ export function getQuotaWithUnit(quota, digits = 6) {
 }
 
 export function renderQuotaWithAmount(amount) {
-  let displayInCurrency = localStorage.getItem('display_in_currency');
-  displayInCurrency = displayInCurrency === 'true';
-  if (displayInCurrency) {
-    return '$' + amount;
-  } else {
+  const quotaDisplayType = localStorage.getItem('quota_display_type') || 'USD';
+  if (quotaDisplayType === 'TOKENS') {
     return renderNumber(renderUnitWithQuota(amount));
   }
+  if (quotaDisplayType === 'CNY') {
+    return '¥' + amount;
+  } else if (quotaDisplayType === 'CUSTOM') {
+    const statusStr = localStorage.getItem('status');
+    let symbol = '¤';
+    try {
+      if (statusStr) {
+        const s = JSON.parse(statusStr);
+        symbol = s?.custom_currency_symbol || symbol;
+      }
+    } catch (e) {}
+    return symbol + amount;
+  }
+  return '$' + amount;
 }
 
 export function renderQuota(quota, digits = 2) {
   let quotaPerUnit = localStorage.getItem('quota_per_unit');
-  let displayInCurrency = localStorage.getItem('display_in_currency');
+  const quotaDisplayType = localStorage.getItem('quota_display_type') || 'USD';
   quotaPerUnit = parseFloat(quotaPerUnit);
-  displayInCurrency = displayInCurrency === 'true';
-  if (displayInCurrency) {
-    const result = quota / quotaPerUnit;
-    const fixedResult = result.toFixed(digits);
-
-    // 如果 toFixed 后结果为 0 但原始值不为 0，显示最小值
-    if (parseFloat(fixedResult) === 0 && quota > 0 && result > 0) {
-      const minValue = Math.pow(10, -digits);
-      return '$' + minValue.toFixed(digits);
-    }
-
-    return '$' + fixedResult;
+  if (quotaDisplayType === 'TOKENS') {
+    return renderNumber(quota);
   }
-  return renderNumber(quota);
+  const resultUSD = quota / quotaPerUnit;
+  let symbol = '$';
+  let value = resultUSD;
+  if (quotaDisplayType === 'CNY') {
+    const statusStr = localStorage.getItem('status');
+    let usdRate = 1;
+    try {
+      if (statusStr) {
+        const s = JSON.parse(statusStr);
+        usdRate = s?.usd_exchange_rate || 1;
+      }
+    } catch (e) {}
+    value = resultUSD * usdRate;
+    symbol = '¥';
+  } else if (quotaDisplayType === 'CUSTOM') {
+    const statusStr = localStorage.getItem('status');
+    let symbolCustom = '¤';
+    let rate = 1;
+    try {
+      if (statusStr) {
+        const s = JSON.parse(statusStr);
+        symbolCustom = s?.custom_currency_symbol || symbolCustom;
+        rate = s?.custom_currency_exchange_rate || rate;
+      }
+    } catch (e) {}
+    value = resultUSD * rate;
+    symbol = symbolCustom;
+  }
+  const fixedResult = value.toFixed(digits);
+  if (parseFloat(fixedResult) === 0 && quota > 0 && value > 0) {
+    const minValue = Math.pow(10, -digits);
+    return symbol + minValue.toFixed(digits);
+  }
+  return symbol + fixedResult;
 }
 
 function isValidGroupRatio(ratio) {
@@ -1072,7 +1119,7 @@ export function renderModelPrice(
       (completionTokens / 1000000) * completionRatioPrice * groupRatio +
       (webSearchCallCount / 1000) * webSearchPrice * groupRatio +
       (fileSearchCallCount / 1000) * fileSearchPrice * groupRatio +
-      (imageGenerationCallPrice * groupRatio);
+      imageGenerationCallPrice * groupRatio;
 
     return (
       <>
@@ -1510,9 +1557,8 @@ export function renderAudioModelPrice(
 }
 
 export function renderQuotaWithPrompt(quota, digits) {
-  let displayInCurrency = localStorage.getItem('display_in_currency');
-  displayInCurrency = displayInCurrency === 'true';
-  if (displayInCurrency) {
+  const quotaDisplayType = localStorage.getItem('quota_display_type') || 'USD';
+  if (quotaDisplayType !== 'TOKENS') {
     return i18next.t('等价金额：') + renderQuota(quota, digits);
   }
   return '';