js_event_loop: reject a non-positive timer interval (#4425)

eventLoop.timer(mode, interval) passes interval straight into
furi_ms_to_ticks() with no validation. For a periodic timer an interval
of 0 divides by zero in furi_event_loop_process_expired_timers()
(elapsed_time / timer->interval) and is counted as expired on every
event-loop pass, so a one-line script - eventLoop.timer("periodic", 0) -
pins the thread running the loop.

Reject interval <= 0 at the binding with a normal script-level error,
matching how the other js_app modules report bad arguments. The <= 0
check also covers negative values that would otherwise wrap to a huge
interval when cast to uint32_t.

Signed-off-by: Cole Munz <colemunz@gmail.com>

Author: munzzyy

applications/system/js_app/modules/js_event_loop/js_event_loop.c

@@ -263,6 +263,11 @@ static void js_event_loop_timer(struct mjs* mjs) {
     int32_t interval;
     JS_VALUE_PARSE_ARGS_OR_RETURN(mjs, &js_loop_timer_args, &mode, &interval);
 
+    if(interval <= 0) {
+        mjs_prepend_errorf(mjs, MJS_BAD_ARGS_ERROR, "timer interval must be a positive number");
+        return;
+    }
+
     JsEventLoop* module = JS_GET_CONTEXT(mjs);
 
     // make timer contract