fix: auto-scan cloud libraries on boot + allow CORS for media playback

- Add BootCloudLibraries() to auto-scan all cloud libraries on startup
- Delay 3s to avoid conflict with system init, scan without auto-scrape
- Enable CORS for /api/cloud/play/* and /api/img to support 3rd-party players
- Fixes issue where each user triggers separate cloud library scans
- Fixes issue where Infuse/Emby apps cannot play cloud resources

internal/service/boot_cloud.go

@@ -0,0 +1,50 @@
+package service
+
+import (
+	"context"
+	"time"
+
+	"go.uber.org/zap"
+
+	"github.com/ShukeBta/MediaStationGo/internal/model"
+)
+
+// BootCloudLibraries 在系统启动后自动扫描所有云盘媒体库，使媒体对所有用户立即可见。
+// 避免每个用户首次访问时都触发扫描。
+func (c *Container) BootCloudLibraries(ctx context.Context) {
+	if c == nil || c.Repo == nil || c.Scan == nil {
+		return
+	}
+	libs, err := c.Repo.Library.List(ctx)
+	if err != nil {
+		c.Log.Warn("boot cloud libraries: list failed", zap.Error(err))
+		return
+	}
+	cloudLibs := make([]model.Library, 0)
+	for _, lib := range libs {
+		if _, ok := ParseCloudLibraryMount(lib.Path); ok {
+			cloudLibs = append(cloudLibs, lib)
+		}
+	}
+	if len(cloudLibs) == 0 {
+		return
+	}
+	c.Log.Info("boot: scheduling cloud library scans", zap.Int("count", len(cloudLibs)))
+	// 延迟3秒后启动，避免和系统初始化任务冲突
+	time.AfterFunc(3*time.Second, func() {
+		for _, lib := range cloudLibs {
+			libID := lib.ID
+			libName := lib.Name
+			go func() {
+				scanCtx, cancel := context.WithTimeout(context.Background(), 2*time.Hour)
+				defer cancel()
+				c.Log.Info("boot: scanning cloud library", zap.String("id", libID), zap.String("name", libName))
+				if _, err := c.Scan.ScanLibraryWithoutAutoScrape(scanCtx, libID); err != nil {
+					c.Log.Warn("boot: cloud library scan failed", zap.String("id", libID), zap.String("name", libName), zap.Error(err))
+				} else {
+					c.Log.Info("boot: cloud library scan completed", zap.String("id", libID), zap.String("name", libName))
+				}
+			}()
+		}
+	})
+}