looprpc: expose static autoloop output

Extend the public rpc surface for static autoloop integration
without turning the planner on yet. SuggestSwaps responses can
now carry static-address loop-in requests and the new planner
reason for missing static candidates is mapped over rpc.

liquidity/liquidity.go

@@ -933,6 +933,10 @@ type Suggestions struct {
 	// InSwaps is the set of loop in swaps that we suggest executing.
 	InSwaps []loop.LoopInRequest
 
+	// StaticInSwaps is the set of static-address loop-ins that we suggest
+	// executing.
+	StaticInSwaps []loop.StaticAddressLoopInRequest
+
 	// DisqualifiedChans maps the set of channels that we do not recommend
 	// swaps on to the reason that we did not recommend a swap.
 	DisqualifiedChans map[lnwire.ShortChannelID]Reason

liquidity/reasons.go

@@ -73,6 +73,11 @@ const (
 	// ReasonCustomChannelData indicates that the channel is not standard
 	// and should not be used for swaps.
 	ReasonCustomChannelData
+
+	// ReasonStaticLoopInNoCandidate indicates that static loop-in
+	// autoloop was selected, but no full-deposit static candidate was
+	// available for the target peer.
+	ReasonStaticLoopInNoCandidate
 )
 
 // String returns a string representation of a reason.
@@ -123,6 +128,9 @@ func (r Reason) String() string {
 	case ReasonLoopInUnreachable:
 		return "loop in unreachable"
 
+	case ReasonStaticLoopInNoCandidate:
+		return "no static loop-in candidate"
+
 	default:
 		return "unknown"
 	}