GitLab

The native Alipay provider previously tried to embed the payment page
URL into a QR code on the client — the URL is not a scannable payload
so the QR never worked. Merchants also hit a H5 detection mismatch
whenever the backend UA sniffer missed iPadOS 13+ or embedded browsers,
and the popup window was too small for Alipay's standard checkout
layout (QR + account-login panel on the right), forcing the user to
scroll horizontally and vertically.

Changes:

Backend
- alipay.go: drop QR-on-URL path. Use redirect-only flow —
  alipay.trade.page.pay for PC (returns a gateway URL the browser
  opens in a new window) and alipay.trade.wap.pay for H5 (returns a
  URL the browser jumps to). Both flows produce pages on
  openapi.alipaydev.com / excashier.alipay.com; the client never
  renders a QR itself.
- payment_handler.go: add optional is_mobile bool to
  CreateOrderRequest so the frontend can declare the device
  explicitly. Server still falls back to UA sniffing when absent.

Frontend
- types/payment.ts, PaymentView.vue: declare is_mobile in
  CreateOrderRequest and pass the computed isMobileDevice() value.
- providerConfig.ts: replace the two fixed POPUP_WINDOW_FEATURES
  constants with getPaymentPopupFeatures(), which prefers 1250×900
  (Alipay's checkout footprint), clamps to window.screen.avail* and
  centers the popup so it never overflows on smaller laptops.
- PaymentQRDialog.vue, PaymentStatusPanel.vue, StripePaymentInline.vue,
  PaymentView.vue: use the new helper at all popup call sites.

- Add recharge_fee_rate system setting (percentage fee on top of recharge amount)
- Full backend chain: config constant, PaymentConfig struct, update validation,
  read/write persistence, DTO, handler GET/PUT responses
- Frontend: settings input with preview, i18n (zh/en), API types
- Fix provider card toggle layout: labels above switches to save width
- Fix Chinese translation: "EasyPay" → "易支付" in provider description

- Add balance_recharge_multiplier system setting (e.g. 1.2 = charge 100 get 120)
- Separate order_amount (credited balance) from pay_amount (actual payment)
- Refund calculates gateway amount proportionally from pay_amount
- Frontend shows both amounts in order details, payment status, refund dialog
- Admin settings UI for configuring recharge multiplier

allow_user_refund:
- Add allow_user_refund field to PaymentProviderInstance ent schema
- Migration 103: ALTER TABLE payment_provider_instances ADD COLUMN
- Cascade logic: disabling refund_enabled auto-disables allow_user_refund
- User refund validation: check provider instance allows user refund
- Admin refund validation: check provider instance allows admin refund
- Subscription refund: deduct days on refund, rollback on failure
- New endpoint: GET /payment/orders/refund-eligible-providers
- Frontend: ToggleSwitch in ProviderCard/Dialog, cascade in SettingsView

Wildcard matching:
- Change findPricingForModel from "longest prefix wins" to "config order
  priority (first match wins)", aligning with channel service behavior

- Restore gateway_cache.go to upstream (no lua embeds)
- Restore payment_order.go to upstream (use out_trade_no lookup)
- Restore payment_fulfillment.go to upstream (same reason)
- Add FeaturesConfig field and IsWebSearchEmulationEnabled to Channel
- Add applyAccountStatsCost wrapper function
- Add SettingKeyWebSearchEmulationConfig constant
- Add WebSearchEmulationEnabled to SystemSettings
- Add notify code rate limiting methods to EmailCache interface
- Remove AllowUserRefund references (ent schema not present)
- Fix duplicate import in payment_handler.go
- Fix wire_gen.go argument mismatches

- Delete payment_channels table and PaymentChannel Ent schema
- Add `features` column to upstream channels table (migration 095)
- Add Features field to Channel struct, input types, handler request/response
- Payment user/admin handlers now use ChannelService directly
- Remove Channel CRUD from PaymentConfigService and admin payment routes
- Remove "渠道管理" tab from admin orders page (use /admin/channels)

Backend:
- Parse EasyPay `payurl2` field, prefer H5 link on mobile
- Add `device=mobile` to EasyPay submit.php (popup) mode
- Expand isMobile detection keywords (add ipad/ipod)

Frontend:
- Add `isMobileDevice()` utility (userAgentData + UA regex)
- Mobile + pay_url: direct redirect instead of QR/popup
- Popup blocked fallback: auto-redirect when window.open fails
- Stripe WeChat Pay: dynamic client param (mobile_web vs web)

Add a full payment and subscription system supporting EasyPay (Alipay/WeChat),
Stripe, and direct Alipay/WeChat Pay providers with multi-instance load balancing.