Move the askrene-inform-channel and askrene-disable-node helpers
from Boss::Mod::FundsMover::Attempter::Impl (where they were
private member functions) into a new shared module
Boss::Mod::AskreneLayer. Lift the "clboss" layer name from a
FundsMover-local constant into a shared constant.
Pure refactor, no behavioral change. Existing tests still
pass (79/79). Done now because PR4 (ActiveProber feeding the
same layer) will be the second producer; sharing avoids
duplicating the JSON construction, the layer-name string, and
the silent-RpcError-catch logic.
The new module exposes three free functions:
- inform_channel_constrained(rpc, layer, scid, dir, amount):
same shape and semantics as Attempter's prior private method.
- inform_channel_succeeded(rpc, layer, scid, dir, amount): new
variant emitting inform=succeeded instead of inform=constrained.
Not used by FundsMover (sendpay failures only carry negative
signals). Added in this commit because the implementation is
one line over the shared internal helper, and PR4's
open-question may have ActiveProber call it on probe-success
to record positive lower-bound observations on probed
channels.
- disable_node(rpc, layer, node_id): same shape and semantics as
Attempter's prior private method.
All three functions silently swallow RpcError, matching the
prior behavior in Attempter. The rationale: if the layer is
unavailable (e.g. CLN < v24.11 where askrene layers do not
exist), the call gracefully degrades to no-op rather than
crashing the caller. Better degraded learning than crashed
plugin.
The layer name "clboss" follows the xpay convention:
persistent shared-knowledge layer = owning plugin name. All
CLBOSS-internal writers (FundsMover today, ActiveProber in
PR4, possibly others later) target the same single layer so
the accumulated knowledge benefits every downstream getroutes
call.
