Timers 1.7.1: a failed LTC capture spawn retries instead of parking

When spawn() itself fails — EACCES on a helper that lost its execute
bit, as the 1.10.2 catalog install did on AB on 2026-10-04 — the child
emits 'error' with no 'exit' to follow. The handler reported the error
but left `child` set and scheduled nothing: the 250 ms eval loop then
kept reporting a misleading "No signal" over the dead child object, and
the listener was parked until a remount.

Null the child in the error handler and retry on the slow timer, the
way spl-listener already does (which is why SPL healed itself the
moment its binary was chmod +x'd, while Timers needed a remount). The
error report stays visible: the eval loop does not report while there
is no child.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

modules/propresenter-timers/ltc-listener.js

@@ -162,7 +162,14 @@ function createLtcListener({ device, channel, moduleDir, log, onUpdate }) {
     });
 
     child.on('error', (err) => {
+      // A spawn that fails (EACCES on a helper that lost its execute bit,
+      // ENOENT) emits 'error' with no 'exit' to follow. Leaving `child` set
+      // would let the eval loop report "No signal" over a dead child forever
+      // and nothing would ever retry — what parked LTC on AB on 2026-10-04.
+      // Null it and retry on the slow timer, the way spl-listener does.
       report({ error: TOOL_MISSING, detail: `LTC capture failed to start: ${err.message}` });
+      child = null;
+      scheduleRestart(BAD_CONFIG_RETRY_MS);
     });
 
     child.on('exit', (code) => {

modules/propresenter-timers/module.json

@@ -1,7 +1,7 @@
 {
   "id": "propresenter-timers",
   "name": "Timers",
-  "version": "1.7.0",
+  "version": "1.7.1",
   "proddash": ">=1.4.0",
   "description": "Timers, Clocks, and LTC From configured Modules",
   "provides": [