feat(server): CreateBatch/生成器切换到 codes 库(Mint 单事务全成或全无)(#codes-lib)

Store 挂库 store(NewStore 内部构造 libcodes.Store,签名不变);
generator.go 三函数委托 libcodes,ErrDuplicate 别名同一哨兵;
Service.CreateBatch 走 libcodes.Mint(签名不变)。openMigratedSQLite
挪到共享 sqlite_helper_test.go,backfill_test.go/service_sqlite_test.go
共用。Store.CreateBatch/CreateCode/CodeExistsByHash 原样保留供
webhook.go(Task 6 改用新原语,Task 7 删除)。

server/internal/codes/service.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/redis/go-redis/v9"
+	libcodes "github.com/wangjia/codes"
 	"github.com/wangjia/pangolin/server/internal/apierr"
 )
 
@@ -322,60 +323,31 @@ type BatchResult struct {
 	Channel      BatchChannel
 }
 
-// CreateBatch generates Count activation codes, writes the batch + code hashes
-// to MySQL, and returns the plaintext codes.  The plaintext codes are the ONLY
-// time they ever appear; the caller is responsible for delivering them securely
-// (e.g., streaming to CSV without logging).
-//
-// Duplicate-hash retries (birthday collision, astronomically unlikely) are
-// handled automatically up to maxRetries per slot.
+// CreateBatch generates Count activation codes via the shared library's Mint
+// (all-or-nothing: batch + code hashes commit in one tx) and returns the
+// plaintext codes — the only time they ever appear.
 func (svc *Service) CreateBatch(ctx context.Context, req BatchRequest) (*BatchResult, error) {
-	const maxRetries = 10
-
-	// Look up plan ID.
-	planID, err := svc.store.GetPlanID(ctx, req.PlanCode)
-	if err != nil {
+	// 未知 plan 先拒(行为等价:旧实现先查 GetPlanID)。
+	if _, err := svc.store.GetPlanID(ctx, req.PlanCode); err != nil {
 		return nil, fmt.Errorf("CreateBatch: unknown plan %s: %w", req.PlanCode, err)
 	}
-
-	// Insert the batch record.
-	batchID, err := svc.store.CreateBatch(ctx, req.Channel, req.CreatedBy, req.Note)
+	ent, err := libcodes.NewDurationEntitlement(string(req.PlanCode), req.DurationDays)
 	if err != nil {
 		return nil, fmt.Errorf("CreateBatch: %w", err)
 	}
-
-	plaintexts := make([]string, 0, req.Count)
-
-	for i := 0; i < req.Count; i++ {
-		var code string
-		var h string
-		ok := false
-		for attempt := 0; attempt < maxRetries; attempt++ {
-			c, err := GenerateCode()
-			if err != nil {
-				return nil, fmt.Errorf("CreateBatch: GenerateCode: %w", err)
-			}
-			h = Hash(c)
-			err = svc.store.CreateCode(ctx, h, planID, req.DurationDays, batchID)
-			if err == ErrDuplicate {
-				continue // collision – generate a fresh code
-			}
-			if err != nil {
-				return nil, fmt.Errorf("CreateBatch: CreateCode: %w", err)
-			}
-			code = c
-			ok = true
-			break
-		}
-		if !ok {
-			return nil, fmt.Errorf("CreateBatch: exceeded %d retry attempts for slot %d", maxRetries, i)
-		}
-		plaintexts = append(plaintexts, code)
+	res, err := libcodes.Mint(ctx, svc.store.Lib(), libcodes.MintRequest{
+		Channel:     string(req.Channel),
+		Entitlement: ent,
+		Count:       req.Count,
+		CreatedBy:   req.CreatedBy,
+		Note:        req.Note,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("CreateBatch: %w", err)
 	}
-
 	return &BatchResult{
-		BatchID:      batchID,
-		Codes:        plaintexts,
+		BatchID:      res.BatchID,
+		Codes:        res.Codes,
 		PlanCode:     req.PlanCode,
 		DurationDays: req.DurationDays,
 		Channel:      req.Channel,