fix: check slot before keepalive to prevent blocking REST call delaying signal pickup

src/events.c

@@ -277,7 +277,25 @@ void *event_executor_thread(void *arg) {
             if (read(fill_wake_fd, &val, sizeof(val)) < 0) {}
         }
 
-        /* Keepalive */
+        /* Check slot BEFORE keepalive — signal takes priority */
+        if (atomic_load_explicit(&slot->state, memory_order_acquire) == EXECUTOR_SLOT_READY) {
+            signal_entry_t sig = slot->signal;
+            atomic_store_explicit(&slot->state, EXECUTOR_SLOT_IN_FLIGHT, memory_order_release);
+
+            executor_execute_triangle(exec, &sig);
+
+            atomic_store_explicit(&slot->state, EXECUTOR_SLOT_FREE, memory_order_release);
+
+            /* Keepalive after execution (if still idle) */
+            int64_t now = now_mono_ms();
+            if (last_keepalive_ms == 0 || now - last_keepalive_ms >= 30000) {
+                executor_keepalive(exec);
+                last_keepalive_ms = now_mono_ms();
+            }
+            continue;
+        }
+
+        /* Keepalive only if slot is not ready */
         int64_t now = now_mono_ms();
         if (last_keepalive_ms == 0 || now - last_keepalive_ms >= 30000) {
             executor_keepalive(exec);