With ColorSource 40, is there a cellphone app I can use to bring up lights for focus sessions?

The AV edition has a built-in Web Remote.

Connect it to a WiFi network, and a QR code appears on Setup > Settings.
If you connect your phone to the same WiFi and scan the QR code the web remote will open on your phone.

The 'standard' edition doesn't have an Ethernet or WiFi connection, but it does support OSC-over-USB devices like #LightHack

From #LightHack:

The #lighthack project is centered around Arduino-based hardware devices that users assemble from scratch. The Arduino connects via a USB COM port and then communicates via OSC with ETC's Eos software.

Eos supports this functionality on consoles running Windows 7 embedded or higher and ETCnomad for Windows in software version 2.6.1 and newer, and on ETCnomad for Mac in software version 2.7.0 and newer.

From #LightHack:

The #lighthack project is centered around Arduino-based hardware devices that users assemble from scratch. The Arduino connects via a USB COM port and then communicates via OSC with ETC's Eos software.

Eos supports this functionality on consoles running Windows 7 embedded or higher and ETCnomad for Windows in software version 2.6.1 and newer, and on ETCnomad for Mac in software version 2.7.0 and newer.

Current Lighthack firmware supports Eos, ColorSource and Cobalt.
github.com/.../lighthack