feat(backend): 出入库编码搜索双路匹配+建单填快照；finance 趋势/日期区间；partner/product 拼音搜索

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JJ1g8XV1YhhmHRzhwWEW7o

backend/internal/handler/finance.go

@@ -2,6 +2,7 @@ package handler
 
 import (
 	"net/http"
+	"strconv"
 	"time"
 
 	"github.com/gin-gonic/gin"
@@ -25,10 +26,13 @@ func (h *FinanceHandler) ListRecords(c *gin.Context) {
 	shopID := middleware.GetShopID(c)
 
 	var q struct {
-		Type     string `form:"type"`
-		Month    string `form:"month"` // e.g. "2026-04"
-		Page     int    `form:"page,default=1"`
-		PageSize int    `form:"page_size,default=50"`
+		Type      string `form:"type"`
+		Month     string `form:"month"` // e.g. "2026-04"
+		StartDate string `form:"start_date"` // YYYY-MM-DD（区间过滤，优先于 month）
+		EndDate   string `form:"end_date"`
+		PartnerID uint64 `form:"partner_id"`
+		Page      int    `form:"page,default=1"`
+		PageSize  int    `form:"page_size,default=50"`
 	}
 	if err := c.ShouldBindQuery(&q); err != nil {
 		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
@@ -43,7 +47,18 @@ func (h *FinanceHandler) ListRecords(c *gin.Context) {
 	if q.Type != "" {
 		base = base.Where("type = ?", q.Type)
 	}
-	if q.Month != "" {
+	if q.PartnerID != 0 {
+		base = base.Where("partner_id = ?", q.PartnerID)
+	}
+	// 日期过滤：区间（本季/自定义）优先；否则按单月。日期串比较跨 MySQL/SQLite 可移植。
+	if q.StartDate != "" || q.EndDate != "" {
+		if q.StartDate != "" {
+			base = base.Where("record_date >= ?", q.StartDate)
+		}
+		if q.EndDate != "" {
+			base = base.Where("record_date <= ?", q.EndDate)
+		}
+	} else if q.Month != "" {
 		base = base.Where("DATE_FORMAT(record_date, '%Y-%m') = ?", q.Month)
 	}
 
@@ -161,6 +176,47 @@ func (h *FinanceHandler) CloseByRef(c *gin.Context) {
 	c.JSON(http.StatusOK, gin.H{"ok": true})
 }
 
+// Trend GET /api/v1/finance/trend?months=6 — 近 N 个自然月收支趋势
+// in=当月出库(销售)额、out=当月入库(采购)额；与 stock Summary 同口径
+// （按 order_date、不筛状态、deleted_at IS NULL），日期串比较跨 MySQL/SQLite 可移植。
+func (h *FinanceHandler) Trend(c *gin.Context) {
+	shopID := middleware.GetShopID(c)
+	months := 6
+	if v := c.Query("months"); v != "" {
+		if n, err := strconv.Atoi(v); err == nil && n >= 1 && n <= 24 {
+			months = n
+		}
+	}
+
+	now := time.Now()
+	first := time.Date(now.Year(), now.Month(), 1, 0, 0, 0, 0, now.Location())
+	type point struct {
+		Month string  `json:"month"`
+		In    float64 `json:"in"`
+		Out   float64 `json:"out"`
+	}
+	sum := func(table, from, to string) float64 {
+		var v float64
+		h.db.Table(table).
+			Where("shop_id = ? AND deleted_at IS NULL AND order_date >= ? AND order_date < ?",
+				shopID, from, to).
+			Select("COALESCE(SUM(total_amount),0)").Scan(&v)
+		return v
+	}
+	const f = "2006-01-02"
+	points := make([]point, 0, months)
+	for i := months - 1; i >= 0; i-- {
+		mStart := first.AddDate(0, -i, 0)
+		mEnd := mStart.AddDate(0, 1, 0)
+		points = append(points, point{
+			Month: mStart.Format("2006-01"),
+			In:    sum("stock_out_orders", mStart.Format(f), mEnd.Format(f)),
+			Out:   sum("stock_in_orders", mStart.Format(f), mEnd.Format(f)),
+		})
+	}
+	c.JSON(http.StatusOK, gin.H{"data": points})
+}
+
 // Summary GET /api/v1/finance/summary — 按往来单位汇总未结清
 func (h *FinanceHandler) Summary(c *gin.Context) {
 	shopID := middleware.GetShopID(c)