feat(forum): P1 topic coupons, P2 plate follow gateway, cash creator revenue

- Topic_Pay: soft/hard coupon validate, payable amount, free-after-discount, paid burn
- Creator_Revenue: settle content/topic/plate_follow cash (type=order), keep shop path
- Plate VIP1/VIP2 meta + resolve_plate_follow_pay_price via aksrt_get_user_vip_level
- New AKSRT_Plate_Follow_Pay REST multi-gateway; remove Credits×100 money bypass
- Frontend: cms-download plate_follow apiKind + forum-governance money cashier bridge

inc/classes/class-aksrt-forum.php

@@ -270,6 +270,18 @@ class AKSRT_Forum {
         return $this->board_service()->is_user_following_plate($user_id, $plate_id);
     }
 
+    public function is_plate_follow_pay_enabled(int $plate_id): bool {
+        return $this->board_service()->is_plate_follow_pay_enabled($plate_id);
+    }
+
+    public function resolve_plate_follow_pay_price(int $plate_id, int $user_id = 0): array {
+        return $this->board_service()->resolve_plate_follow_pay_price($plate_id, $user_id);
+    }
+
+    public function mark_plate_followed(int $user_id, int $plate_id): void {
+        $this->board_service()->mark_plate_followed($user_id, $plate_id);
+    }
+
     public function toggle_follow_plate(int $user_id, int $plate_id): array {
         return $this->board_service()->toggle_follow_plate($user_id, $plate_id);
     }