feat: Add Bolt11Invoice interface and wrapper implementation for FFI bindings

- Convert Bolt11Invoice from string type to full interface in UDL
- Define required Bolt11Invoice methods in the UDL interface (expiry_time_seconds, min_final_cltv_expiry_delta, amount_milli_satoshis, is_expired, etc.)
- Create Bolt11Invoice struct in uniffi_types.rs to wrap LdkBolt11Invoice
- Implement methods required by the UDL interface
- Add From/Into implementations for conversion between wrapper and LDK types
- Add tests for the wrapper struct

Author: alexanderwiederin

bindings/ldk_node.udl

@@ -698,6 +698,45 @@ dictionary NodeAnnouncementInfo {
 	sequence<SocketAddress> addresses;
 };
 
+enum Currency {
+	"Bitcoin",
+	"BitcoinTestnet",
+	"Regtest",
+	"Simnet",
+	"Signet",
+};
+
+dictionary RouteHintHop {
+	PublicKey src_node_id;
+	u64 short_channel_id;
+	u16 cltv_expiry_delta;
+	u64? htlc_minimum_msat;
+	u64? htlc_maximum_msat;
+	RoutingFees fees;
+};
+
+interface Bolt11Invoice {
+	[Throws=NodeError, Name=from_str]
+	constructor([ByRef] string invoice_str);
+	sequence<u8> signable_hash();
+	u64 expiry_time_seconds();
+	u64 min_final_cltv_expiry_delta();
+	u64? amount_milli_satoshis();
+	boolean is_expired();
+	u64 seconds_since_epoch();
+	boolean would_expire(u64 at_time_seconds);
+	u64 seconds_until_expiry();
+	PaymentHash payment_hash();
+	u64 timestamp_seconds();
+	Currency currency();
+	PaymentSecret payment_secret();
+	Bolt11InvoiceDescription description();
+	sequence<Address> fallback_addresses();
+	sequence<sequence<RouteHintHop>> route_hints();
+	PublicKey recover_payee_pub_key();
+	Network network();
+};
+
 [Custom]
 typedef string Txid;
 
@@ -716,9 +755,6 @@ typedef string NodeId;
 [Custom]
 typedef string Address;
 
-[Custom]
-typedef string Bolt11Invoice;
-
 [Custom]
 typedef string Offer;