fix(timer): ensure timer loop is asyncSpawned

codex/utils/timer.nim

@@ -30,13 +30,13 @@ proc new*(T: type Timer, timerName = "Unnamed Timer"): Timer =
   ## Create a new Timer intance with the given name
   Timer(name: timerName)
 
-proc timerLoop(timer: Timer) {.async.} =
+proc timerLoop(timer: Timer) {.async: (raises: []).} =
   try:
     while true:
       await timer.callback()
       await sleepAsync(timer.interval)
   except CancelledError:
-    raise
+    discard # do not propagate as timerLoop is asyncSpawned
   except CatchableError as exc:
     error "Timer caught unhandled exception: ", name=timer.name, msg=exc.msg
 
@@ -47,6 +47,7 @@ method start*(timer: Timer, callback: TimerCallback, interval: Duration) {.base.
   timer.callback = callback
   timer.interval = interval
   timer.loopFuture = timerLoop(timer)
+  asyncSpawn timer.loopFuture
 
 method stop*(timer: Timer) {.async, base.} =
   if timer.loopFuture != nil: