chore: 补提测试修复、新增测试工具和设计文档

- fix(test): 同步 listInventory 签名（补 series/spec 参数）
- test(backend): 新增 import_parse_test.go
- chore(backend): 新增 cmd/test_xls 调试工具
- docs: UI 筛选组件设计规范、Gemini 项目配置

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/cmd/test_xls/main.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	xls "github.com/extrame/xls"
+)
+
+func safeXlsRow(sheet *xls.WorkSheet, r int) (row *xls.Row) {
+	defer func() { recover() }()
+	return sheet.Row(r)
+}
+
+func main() {
+	wb, err := xls.Open("/Users/wangjia/.claude/jobs/4f07558d/tmp/test_150rows.xls", "utf-8")
+	if err != nil {
+		fmt.Println("open error:", err)
+		return
+	}
+	sheet := wb.GetSheet(0)
+	if sheet == nil {
+		fmt.Println("no sheet")
+		return
+	}
+	fmt.Printf("MaxRow: %d\n", sheet.MaxRow)
+
+	numCols := 0
+	headerRow := sheet.Row(0)
+	fmt.Printf("Header LastCol: %d\n", headerRow.LastCol())
+	for c := 0; c < headerRow.LastCol(); c++ {
+		v := strings.TrimSpace(headerRow.Col(c))
+		if v != "" {
+			numCols = c + 1
+		}
+	}
+	if numCols == 0 {
+		numCols = 20
+	}
+	fmt.Printf("numCols: %d\n", numCols)
+
+	const maxRows = 100000
+	const maxEmpty = 5
+	emptyStreak := 0
+	rowCount := 0
+	for r := 0; r < maxRows; r++ {
+		row := safeXlsRow(sheet, r)
+		cells := make([]string, numCols)
+		isEmpty := true
+		if row != nil {
+			for c := 0; c < numCols; c++ {
+				cells[c] = strings.TrimSpace(row.Col(c))
+				if cells[c] != "" {
+					isEmpty = false
+				}
+			}
+		}
+		if isEmpty {
+			emptyStreak++
+			if emptyStreak >= maxEmpty {
+				fmt.Printf("Breaking at r=%d after %d empty streak\n", r, emptyStreak)
+				break
+			}
+			rowCount++
+			continue
+		}
+		emptyStreak = 0
+		rowCount++
+	}
+	fmt.Printf("Total rows read: %d\n", rowCount)
+}