Minor appearance changes, sharing live preview

backend/handlers/sharing.go

@@ -2,6 +2,7 @@ package handlers
 
 import (
 	"fmt"
+	"mime"
 	"os"
 	"path/filepath"
 	"time"
@@ -203,10 +204,16 @@ func (h *ShareHandler) GetPublicShare(c *fiber.Ctx) error {
 	// For simplicity, we'll return a short-lived download token JWT.
 	// Actually, easier: the frontend calls GET /api/public/download/:id?pwd=xxx
 	
+	mimeType := mime.TypeByExtension(filepath.Ext(info.Name()))
+	if mimeType == "" {
+		mimeType = "application/octet-stream"
+	}
+
 	return c.JSON(fiber.Map{
 		"name": filepath.Base(path),
 		"size": info.Size(),
 		"is_dir": info.IsDir(),
+		"mime_type": mimeType,
 	})
 }