Add an LSPS2-aware BOLT12 router wrapper

Introduce `LSPS2BOLT12Router` to map registered offers to LSPS2 invoice
parameters and build blinded payment paths through the negotiated
intercept `SCID`. All other routing behavior still delegates to the
wrapped router.

Co-Authored-By: HAL 9000

Author: tnull

lightning-liquidity/src/lsps2/mod.rs

@@ -13,5 +13,6 @@ pub mod client;
 pub mod event;
 pub mod msgs;
 pub(crate) mod payment_queue;
+pub mod router;
 pub mod service;
 pub mod utils;