fix: no reconnect storm on send failure, reduce refresh to 1 FPS

- try_send: don't reconnect on failure, just skip and retry next cycle
- Background refresh: 5 FPS → 1 FPS to reduce router serial load
- Revert Bridge.run() - RouterBridge uses Zephyr RTOS thread

scripts/led-matrix-viz.py

@@ -12,7 +12,7 @@ ROUTER_SOCK = os.environ.get("ROUTER_SOCK", "/var/run/arduino-router.sock")
 COLS = 13
 ROWS = 8
 
-REFRESH_INTERVAL = 0.2
+REFRESH_INTERVAL = 1.0
 
 STATS_FILE = "/tmp/viz-stats.json"
 _poll = select.poll()
@@ -60,11 +60,7 @@ def try_send(router, data):
         router.sendall(data)
         return router, True
     except (BlockingIOError, OSError):
-        try:
-            router.close()
-        except OSError:
-            pass
-        return connect_router(), False
+        return router, False
 
 
 def main():