Description
This branch replaces the fixed startup delay in pyrogue.protocols.UdpRssiPack with an explicit readiness-based flow for programming the UDP RX buffer count.

The underlying issue is that RSSI parameter negotiation completes asynchronously, and only the client side was waiting for link-open before using curMaxBuffers(). That meant the server side could read and apply the pre-negotiation buffer depth too early. The old time.sleep(0.25) masked this race, but it did not actually solve it.

What changed:

• Removed the blind startup delay approach
• Kept the existing client-side synchronous behavior:
  • if wait=True and client mode, _start() waits for RSSI open before applying negotiated RX buffer depth
• Changed the server-side behavior:
  • _start() no longer tries to apply negotiated RX buffer depth immediately
  • instead, it defers the setRxBufferCount(curMaxBuffers()) call until RSSI actually reaches open state
• Added small internal state to ensure the negotiated RX buffer count is applied once and cleaned up correctly on stop

Why:

• curMaxBuffers() is only stable after RSSI negotiation
• on the server side, blocking _start() until open can deadlock when both endpoints are managed under the same Root
• so the correct fix is:
  • synchronous wait on the client side
  • deferred update on the server side

Result:

• removes the fixed sleep
• avoids the server-side race
• avoids introducing same-process startup deadlock