ln/lightning: watchdog recycles zombie receive-listener socket

Port of master bd1ece3 to staging. When cl restarts (e.g. autoheal after a
healthcheck timeout), the app's waitanyinvoice long-poll can hang on the now-dead
listen socket: listenerActive stays true forever, nothing restarts it, and
incoming lightning payments silently stop crediting until a manual app restart.
The per-call RPC timeout can't catch this — waitanyinvoice is meant to block.

ensureListenerAlive (run every 120s) now also detects a stalled listener — active
but blocked in waitanyinvoice for >5min — probes cl via the main socket (getinfo),
and only if cl is actually alive treats the listen socket as a zombie: bumps a
listenerEpoch, calls lnListen.reset() (new: drops the proxy socket so the next
call reconnects), and re-arms. The epoch guard makes the wedged invocation bow out
when its waitanyinvoice finally rejects, so we never run two listeners or
double-credit.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

1 files changed, 2 insertions, 1 deletions

diff --git a/index.ts b/index.ts
index a664638d..98a9668e 100644
--- a/index.ts
+++ b/index.ts
@@ -5,7 +5,7 @@ import { admin, auth, optional } from "$lib/auth";
 import { getDelegateInfo, receiveDelegation } from "$lib/delegator";
 import { g, s } from "$lib/db";
 
-import { fixBolt12, listenForLightning, replay } from "$lib/lightning";
+import { ensureListenerAlive, fixBolt12, listenForLightning, replay } from "$lib/lightning";
 import { l } from "$lib/logging";
 import { startHealthCheck } from "$lib/health";
 import { getLocations } from "$lib/locations";
@@ -49,6 +49,7 @@ setTimeout(listenForLightning, 2000);
 listenForDMs();
 initMlsIndex();
 setInterval(sendHeartbeat, 2000);
+setInterval(ensureListenerAlive, 120_000); // LN listener watchdog
 
 app.get("/balances", info.balances);
 app.get("/health", info.health);