fix: json syntax error in bt config (#1014)

internal/protocol/bt/config.go

@@ -4,7 +4,7 @@ type config struct {
 	ListenPort int      `json:"listenPort"`
 	Trackers   []string `json:"trackers"`
 	// SeedKeep is always keep seeding after downloading is complete, unless manually stopped.
-	SeedKeep bool `json:"seedKeep`
+	SeedKeep bool `json:"seedKeep"`
 	// SeedRatio is the ratio of uploaded data to downloaded data to seed.
 	SeedRatio float64 `json:"seedRatio"`
 	// SeedTime is the time in seconds to seed after downloading is complete.