Add support for Calculate Linux

Calculate Linux is based on Gentoo with some precompiled binaries so users don't have to compile everything from the get go. It's a good system and Brave is the best which is unsupported yet.

Maybe y'all should just create brave.appimage for libc and musl.

Linux 6.12.16-calculate #1 SMP PREEMPT_DYNAMIC Fri May 23 13:31:45 UTC 2025 x86_64 GNU/Linux

#------------------------------------------------------------------------------
# Modified Calculate Utilities 3.7.6.8
# Processed template files:
#------------------------------------------------------------------------------
NAME="Calculate"
ID="calculate"
PRETTY_NAME="Calculate Linux Desktop Cinnamon"
ANSI_COLOR="1;32"
HOME_URL="https://www.calculate-linux.org"
SUPPORT_URL="https://chat.calculate-linux.org"
BUG_REPORT_URL="https://forum.calculate-linux.org"
VERSION_ID="2.17"
ID_LIKE="gentoo calculate"
BUILD_ID=20250622
DOCUMENTATION_URL="https://wiki.calculate-linux.org"
VARIANT_ID=desktop

Start by reading install.sh, especially its Linux distribution and libc detection paths. Compare the existing package selection with the Calculate Linux details in the issue and determine whether libc or musl support is required; done means the installer recognizes Calculate Linux and selects an appropriate Brave package.

Written by the indexing model from the issue text.