Optimize collector loop to account for actual execution time.

Previously, the loop did not consider the time spent on `collect_once`, potentially causing delays. By adjusting the sleep duration dynamically, the poll interval remains consistent as intended.

backend/app/services/collector.py

@@ -271,8 +271,11 @@ async def collect_once() -> None:
 
 async def collector_loop(stop_event: asyncio.Event) -> None:
     while not stop_event.is_set():
+        cycle_started = asyncio.get_running_loop().time()
         await collect_once()
+        elapsed = asyncio.get_running_loop().time() - cycle_started
+        sleep_for = max(0.0, settings.poll_interval_seconds - elapsed)
         try:
-            await asyncio.wait_for(stop_event.wait(), timeout=settings.poll_interval_seconds)
+            await asyncio.wait_for(stop_event.wait(), timeout=sleep_for)
         except asyncio.TimeoutError:
             pass