BLE: Delay reconnect 2s after disconnect

[bjorkert]

Improve BLE reconnect behavior after disconnect

What

• On didDisconnectPeripheral, schedule reconnect after 2 seconds.
• Cancel any outstanding connect-timeout timer.
• Only reconnect if Central is powered on and the peripheral isn’t already .connecting/.connected.

Why

• Some Anubis transmitters briefly stay “alive” or do a quick connection flurry after a disconnect. An immediate reconnect can keep the radio active and increase battery use. A short 2s debounce lets the transmitter finish powering down/settling, reducing churn and power draw.

[bjorkert]

Loop also does a 2 second pause before reconnecting. I am currently using this in-vivo.

[codebymini]

Approved based on code-review