Where is the sources? Could you share it?

Sorry, but I do not plan to share my sources. If you want to create your device, you can download TI Z-Stack for the corresponding device and build firmware from included examples.

How to reset (re-join) a device?

Option 1
CC253x: Re-flash firmware
Option 2
CC2530: Power on, wait 2 seconds, power off, repeat this cycle three times.
CC2531: Power on, press and hold down the S2 button for 5 seconds.
Option 3
CC2530 device with my configurable firmware: Power on, press and hold down the button on “Input 1” for 10 seconds.

Does your router for CC2531 or CC2531 have a status LED?

The standard firmware supports LED for CC2531 only. You may download a configurable firmware, disable all inputs and outputs, but configure a status LED pin. That firmware also works as a router.