feat: optional property rent

Off unless property_rent_enabled is on. Each property world's rent comes from its PropertyTemplate
row (minimumPrice every rentDuration x durationType; Block Yard is free), unless the new Property
Rent dashboard page sets another price or period (property_rent_manage). Rent is taken from the
owner's coins shortly after their character loads, with a mail receipt; unpaid rent is mailed and,
after property_rent_grace_days, makes the property private until it is paid, like live. The
property management component refuses public or best friends privacy while rent is overdue and a
property world that loads overdue makes itself private. Property game messages are unchanged.

Fixes #943

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dDatabase/GameDatabase/ITables/IPropertyRent.h

@@ -0,0 +1,45 @@
+#ifndef __IPROPERTYRENT__H__
+#define __IPROPERTYRENT__H__
+
+#include <cstdint>
+#include <string>
+#include <vector>
+
+#include "dCommonVars.h"
+
+/**
+ * Property rent (see dCommon/PropertyRentRules.h): the dashboard's per-world prices and what an owner's properties owe.
+ */
+class IPropertyRent {
+public:
+	struct RentRate {
+		uint32_t mapId{};
+		int64_t price{};        // 0: free
+		int32_t periodDays{};   // 0: the PropertyTemplate's period
+		std::string updatedBy;
+		int64_t updatedAt{};
+	};
+
+	struct OwnedProperty {
+		LWOOBJID id{};
+		uint32_t zoneId{};
+		int32_t privacyOption{};
+		int64_t rentDue{};      // 0: never charged
+		std::string name;
+	};
+
+	virtual std::vector<RentRate> GetPropertyRentRates() = 0;
+	// Insert or replace the row of rate.mapId
+	virtual void SetPropertyRentRate(const RentRate& rate) = 0;
+	virtual bool DeletePropertyRentRate(uint32_t mapId) = 0;
+
+	// The properties a character owns
+	virtual std::vector<OwnedProperty> GetPropertiesOfOwner(LWOOBJID ownerId) = 0;
+	// The property's rent_due (0 when there is no such property)
+	virtual int64_t GetPropertyRentDue(LWOOBJID propertyId) = 0;
+	// Record a payment (or where the grace period starts): rent_amount and rent_due
+	virtual void SetPropertyRent(LWOOBJID propertyId, int64_t amount, int64_t due) = 0;
+	virtual void SetPropertyPrivacy(LWOOBJID propertyId, int32_t privacyOption) = 0;
+};
+
+#endif  //!__IPROPERTYRENT__H__