Re-claim inbound payments when preimage is already known

When a PaymentClaimable event arrives for a payment already marked as
Succeeded or Spontaneous in the payment store, re-claim using the
stored preimage instead of failing the HTLC backwards. This prevents
fund loss in scenarios where the channel monitor state was not yet
persisted (e.g. with deferred monitor writes) but the payment store
already recorded the claim as successful.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: joostjager

src/event.rs

@@ -673,6 +673,26 @@ where
 					if info.status == PaymentStatus::Succeeded
 						|| matches!(info.kind, PaymentKind::Spontaneous { .. })
 					{
+						let stored_preimage = match info.kind {
+							PaymentKind::Bolt11 { preimage, .. }
+							| PaymentKind::Bolt11Jit { preimage, .. }
+							| PaymentKind::Bolt12Offer { preimage, .. }
+							| PaymentKind::Bolt12Refund { preimage, .. }
+							| PaymentKind::Spontaneous { preimage, .. } => preimage,
+							_ => None,
+						};
+
+						if let Some(preimage) = stored_preimage {
+							log_info!(
+								self.logger,
+								"Re-claiming previously succeeded payment with hash {} of {}msat",
+								hex_utils::to_string(&payment_hash.0),
+								amount_msat,
+							);
+							self.channel_manager.claim_funds(preimage);
+							return Ok(());
+						}
+
 						log_info!(
 							self.logger,
 							"Refused duplicate inbound payment from payment hash {} of {}msat",