Add referral bonus configuration and enhance payment processing logic

- Introduced a new environment variable REFERRAL_ONE_BONUS_PER_REFEREE to control referral bonus application.
- Updated referral bonus application logic to skip bonuses for users with active subscriptions at the time of payment.
- Enhanced payment processing functions across multiple services to include current payment ID and skip logic for active users.
- Added a new database method to count succeeded payments for users, improving referral bonus eligibility checks.

config/settings.py

@@ -93,6 +93,12 @@ class Settings(BaseSettings):
     REFERRAL_BONUS_DAYS_REFEREE_12_MONTHS: Optional[int] = Field(
         default=15, alias="REFEREE_BONUS_DAYS_12_MONTHS")
 
+    # Referral program configuration
+    REFERRAL_ONE_BONUS_PER_REFEREE: bool = Field(
+        default=True,
+        description="When true, referral bonuses (for inviter and referee) are applied only once per invited user – on their first successful payment."
+    )
+
     PANEL_API_URL: Optional[str] = None
     PANEL_API_KEY: Optional[str] = None
     USER_TRAFFIC_LIMIT_GB: Optional[float] = Field(default=0.0)