fix(startup): reduce auto-detection retries to minimize startup delay

[OmkarSarkar204]

Fixes #1198

Problem

The application hangs for approximately 2 seconds on startup when no flight controller is connected. This is caused by the auto-detection logic using the default 3 retries for every checked port.

Solution

• Updated _register_and_try_connect to accept a retries parameter.
• Changed the auto-detection loop to use retries=2 (1 initial attempt + 1 retry).
• Added a test to verify the retry count.

2026-01-23 02:05:44,366 - INFO - Will connect to /dev/ttyS9 @ 115200 baud
2026-01-23 02:05:44,366 - INFO - Will connect to tcp:127.0.0.1:5760
[Errno 111] Connection refused sleeping
2026-01-23 02:05:45,367 - INFO - Will connect to udp:0.0.0.0:14550

Reasoning

Set retries=2 ensures there is still one safety retry for SITL, as suggested, but reduces the startup delay.