init: hgmj server initial commit

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

common/enum/imad/position.go

@@ -0,0 +1,15 @@
+package imad
+
+import "strings"
+
+const (
+	ListBanner          = "IM_LIST_BANNER"
+	ListFeedNative      = "IM_LIST_FEED_NATIVE"
+	ChatNotificationBar = "IM_CHAT_NOTIFICATION_BAR"
+	ChatFloatingGifBall = "IM_CHAT_FLOATING_GIF_BALL"
+)
+
+// IsPositionCode reports whether code is an IM ad-center location identifier.
+func IsPositionCode(code string) bool {
+	return strings.HasPrefix(strings.TrimSpace(code), "IM_")
+}