Add console cable plug-in order warning and console vs SSH note

Cable must be connected before powering on for screen/picocom to work.
Also clarify that console is one-time setup only; script uses SSH over Ethernet.

https://claude.ai/code/session_01JR2EMK7rwrZJowpstcaxQ6

README.md

@@ -34,7 +34,7 @@ Search **"RJ45 to USB console cable Cisco compatible"** — around $8. This is t
 
 ### Step 3 — Connect and Open a Terminal
 
-Plug the RJ-45 end into the switch console port. Plug USB into your laptop.
+**Important:** Plug the console cable in — both the RJ-45 end into the switch and the USB end into your laptop — **before** powering on the switch. If you plug in after power-on, `screen` and `picocom` may not detect the device correctly.
 
 **Settings:** `9600 baud · 8 data bits · No parity · 1 stop bit · No flow control`
 
@@ -51,6 +51,8 @@ To find your COM/device name if unsure:
 - Mac: `ls /dev/tty.usb*` before and after plugging in
 - Windows: Device Manager → Ports (COM & LPT)
 
+> **Console vs SSH:** The console cable gives you direct CLI access to type commands on the switch. It is only needed for initial setup. Once SSH is configured, the management script connects over Ethernet (port 22) and you never need the console cable again — unless you lock yourself out.
+
 ---
 
 ### Step 4 — Power On and Read the Boot Screen