init: 毛孩子计划 小程序 + Go 后端 + 内嵌后台

- pets-fe: 微信原生小程序（首页/计划/记录/报告/社区/引导），
  服务端驱动、无假数据；弹层改用 scroll-view，打开时隐藏自定义 tabBar
- pets-be: Gin + GORM(MySQL, sundynix_ 前缀) + MinIO，统一响应/分页，
  微信 code2session 登录，provider-neutral AI(DeepSeek)，go:embed React 后台
- 修复：分段选择类型不匹配（字符串 vs 数字）导致选不中

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

pets-be/internal/handler/upload.go

@@ -0,0 +1,42 @@
+package handler
+
+import (
+	"fmt"
+	"path"
+	"strings"
+	"time"
+
+	"github.com/gin-gonic/gin"
+
+	"github.com/sundynix/pets-be/internal/middleware"
+	"github.com/sundynix/pets-be/pkg/response"
+)
+
+// Upload POST /api/upload  multipart/form-data，字段名 file
+func (h *Handler) Upload(c *gin.Context) {
+	fileHeader, err := c.FormFile("file")
+	if err != nil {
+		response.FailParams(c, "缺少上传文件 file")
+		return
+	}
+	src, err := fileHeader.Open()
+	if err != nil {
+		response.FailErr(c, err)
+		return
+	}
+	defer src.Close()
+
+	ext := strings.ToLower(path.Ext(fileHeader.Filename))
+	objectName := fmt.Sprintf("uploads/%d/%d%s", middleware.UserID(c), time.Now().UnixNano(), ext)
+	contentType := fileHeader.Header.Get("Content-Type")
+	if contentType == "" {
+		contentType = "application/octet-stream"
+	}
+
+	url, err := h.svc.Upload(objectName, src, fileHeader.Size, contentType)
+	if err != nil {
+		response.FailErr(c, err)
+		return
+	}
+	response.OK(c, gin.H{"url": url})
+}