GitLab

Introduce a sentinel ErrOrderNotFound in the payment service layer so the
webhook handler can distinguish "the out_trade_no does not exist in our DB"
from other fulfillment failures, and downgrade the former to a WARN log +
success response.

Background
- Providers (Stripe, Alipay, Wxpay, EasyPay, ...) retry webhooks whenever
  we answer non-2xx. When a webhook endpoint is misconfigured (e.g. a
  foreign environment points at us) or our orders table has been wiped,
  we return 500 forever and the provider retries for days, spamming logs.
- The old code also collapsed "order not found" and "DB query failed" into
  the same branch — a DB blip would be reported as "order not found" and
  swallowed.

Service layer (payment_fulfillment.go)
- Add `var ErrOrderNotFound = errors.New("payment order not found")`.
- In HandlePaymentNotification, distinguish the two error paths:
  * dbent.IsNotFound(err) → wrap with ErrOrderNotFound so callers can
    errors.Is(...) it.
  * anything else → wrap the original err with %w so it still bubbles up
    as 500 and the provider retries (DB hiccup should be retried).

Handler layer (payment_webhook_handler.go)
- Before returning 500, check errors.Is(err, service.ErrOrderNotFound):
  emit a WARN (with provider / outTradeNo / tradeNo for discoverability),
  then call writeSuccessResponse so the provider sees its expected 2xx
  body (Stripe empty body / Wxpay JSON / others "success").
- Other errors retain the existing 500 behavior.

Monitoring note: because this path now swallows unknown-order webhooks
silently from the provider's perspective, the WARN log line is the only
signal. Alert on "unknown order, acking to stop retries" if you want
visibility into misrouted webhooks or accidental data loss.

Bug fixes:
- Detached context for GetAccountConcurrencyBatch (prevent all-zero on request cancel)
- Filter soft-deleted users in GetByGroupID
- Stripe CSP policy (allow Stripe.js in script-src and frame-src)
- WebSearch API key validation on save
- RECHARGING status in payment result success check
- Windows test fixes (logger Sync deadlock, config path escaping)

Feature enhancements:
- Webhook multi-instance dispatch (extractOutTradeNo + GetWebhookProvider)
- EasyPay mobile H5 payment (device param + PayURL2)
- SSE error propagation in WebSearch emulation
- AccountStatsCost DTO field for admin usage logs
- Plans sort by sort_order instead of created_at
- UsageMapHook for streaming response usage data
- apicompat Instructions field passthrough
- EffectiveLoadFactor for ops concurrency/metrics
- Usage billing RETURNING balance for notify system
- BulkUpdate mixed channel warning with details
- println to slog migration in auth cache
- Wire ProviderSet cleanup
- CI cache-dependency-path optimization

Frontend:
- Refund eligibility check per provider (canRequestRefund)
- Plan sort_order editing
- Dead code cleanup (simulate_claude_max, client_affinity)
- GroupsView platform switch guard
- channels features_config API type
- UsageView account_stats_cost export

Backend:
- Extract YuanToFen/FenToYuan to payment/amount.go using shopspring/decimal
- Require alipay publicKey in config validation
- Fix wxpay webhook response to return JSON per V3 spec
- Remove wxpay certSerial fallback to publicKeyId
- Define magic strings as named constants in wxpay/alipay providers
- Add slog warning for wxpay H5→Native payment downgrade
- Make EncryptionKey validation return error on invalid (non-empty) key
- Make decryptConfig propagate errors instead of returning nil
- Add idempotency check in doBalance to prevent stuck FAILED retries

Frontend:
- Fix dashboard currency symbol from $ to ¥
- Fix AdminPaymentPlansView any type to proper SubscriptionPlan type
- Make quick amount buttons follow selected payment method limits
- Center help image with larger height and text below

Backend:
- Split payment_order.go (546→314 lines) into payment_order_lifecycle.go
- Replace magic strings with constants in factory, easypay, webhook handler
- Add rate limit/validity unit constants in payment_order_lifecycle, payment_service
- Fix critical regression: add PaymentEnabled to GetPublicSettings response
- Add missing migration 099_fix_migrated_purchase_menu_label_icon.sql

Frontend:
- Fix StripePopupView.vue: replace `as any` with typed interface, use extractApiErrorMessage
- Fix AdminOrderTable.vue: replace hardcoded column labels with i18n t() calls
- Fix SubscriptionsView.vue: replace hardcoded Today/Tomorrow with i18n
- Extract duplicate statusBadgeClass/canRefund/formatOrderDateTime to orderUtils.ts
- Add missing i18n keys: common.today, common.tomorrow, payment.orders.orderType/actions
- Remove dead PurchaseSubscriptionView.vue (replaced by PaymentView)

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