Remove unused recycle bin and add optional local file delete (#26)

Soft-delete restore/purge/list and the recycle_purge job are gone.
Admin delete now removes library index rows, with an optional
delete_files query that also deletes local media + sidecar NFO.
UI copy is renamed from 移入回收站 to 删除, with a confirm checkbox.

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: truewhile <truewhile@users.noreply.github.com>

internal/handler/media_delete.go

@@ -0,0 +1,35 @@
+// Package handler — media delete endpoint.
+package handler
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+
+	"github.com/truewhile/MeBox/internal/service"
+)
+
+func deleteMediaHandler(svc *service.Container) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		deleteFiles := parseDeleteFilesQuery(c.Query("delete_files"))
+		if err := svc.Media.DeleteMedia(c.Request.Context(), c.Param("id"), deleteFiles); err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+		c.Status(http.StatusNoContent)
+	}
+}
+
+func parseDeleteFilesQuery(raw string) bool {
+	raw = strings.TrimSpace(strings.ToLower(raw))
+	if raw == "" {
+		return false
+	}
+	if raw == "1" || raw == "true" || raw == "yes" {
+		return true
+	}
+	v, err := strconv.ParseBool(raw)
+	return err == nil && v
+}