Add Ubuntu/Debian installer and auto-detection

[Neil-Lunavat]

Summary

• Adds ubuntu-install.sh: a full installer for Ubuntu/Debian-based distros, mirroring the Fedora installer but using apt. Tested on Ubuntu 24.04 LTS with GNOME 46 on an HP Victus 16.
• install.sh now auto-detects Ubuntu/Debian via /etc/os-release (matching ubuntu, debian, linuxmint, pop) with an apt-get fallback, routing to ubuntu-install.sh.

What the Ubuntu installer does

Same pipeline as fedora-install.sh:

1. Installs deps via apt-get: meson, ninja-build, libgtk-4-dev, linux-headers-$(uname -r), dkms, g++, git
2. Creates victus / victus-backend groups and victus-backend system user
3. Installs helper scripts and sudoers rules
4. Clones and builds the hp-wmi-fan-and-backlight-control DKMS module
5. Builds and installs the GTK4 app + backend via meson
6. Installs udev rules and starts victus-backend.service

Hardware tested

Model	OS	GNOME	Result
HP Victus 16	Ubuntu 24.04 LTS	46.0	✅ Working

Secure Boot note

Users with Secure Boot enabled must either:

• Disable Secure Boot in BIOS (simplest), or
• Enroll the shim MOK key: sudo mokutil --import /var/lib/shim-signed/mok/MOK.der, then reboot and confirm in the MokManager screen

Test plan

• sudo ./install.sh completes without errors on Ubuntu 24.04
• systemctl is-active victus-backend.service returns active
• Fan mode switching works in the GTK app and GNOME extension
• gnome-extensions enable victus-control@victus enables the panel extension

[Batuhan4]

@Neil-Lunavat I pushed a follow-up commit onto this PR branch (c85c135) to address the review blockers.

Changes in that commit:

• make hp_wmi DKMS detection accept both /extra and /updates/dkms
• keep the same module-path check consistent in the boot-time healthcheck
• add sudo to the Ubuntu installer dependency list
• sync the README with the new Ubuntu/Debian installer path

Can you please re-test on the Ubuntu 24.04 machine you used originally, ideally from a clean state, and confirm these specifically?

• sudo ./install.sh completes without manual fixes
• modprobe --show-depends hp_wmi resolves to the DKMS-installed module and install does not fail on /updates/dkms
• systemctl is-active victus-backend.service is active
• fan mode switching still works in the GTK app / GNOME extension
• if Secure Boot is enabled, whether the MOK flow is still the only extra step needed

If you have access to another Debian-based distro as well, one extra smoke test there would help validate the broader auto-detection claim.

[selvatharrun]

Hi @Batuhan4 tried the fix, after u fixed the DKMS detection, and the one before, neither of them worked both resulting in the same error

"""
dkms is already the newest version (3.2.2-1ubuntu1).
g++ is already the newest version (4:15.2.0-5ubuntu1).
sudo is already the newest version (1.9.17p2-1ubuntu3).
linux-headers-7.0.0-15-generic is already the newest version (7.0.0-15.15).
Solving dependencies... Done
The following packages were automatically installed and are no longer required:
linux-headers-7.0.0-14 linux-headers-7.0.0-14-generic linux-image-unsigned-7.0.0-14-generic linux-main-modules-zfs-7.0.0-14-generic linux-modules-7.0.0-14-generic linux-tools-7.0.0-14 linux-tools-7.0.0-14-generic
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
--> Creating secure users and groups...
Group 'victus' already exists.
Group 'victus-backend' already exists.
User 'victus-backend' already exists.
--> Installing helper scripts and sudoers...
--> Installing patched hp-wmi kernel module...
From https://github.com/Batuhan4/hp-wmi-fan-and-backlight-control

• branch master -> FETCH_HEAD
  HEAD is now at 6368256 docs: expand tested laptop matrix
  Module hp-wmi-fan-and-backlight-control/0.0.2 for kernel 7.0.0-15-generic (x86_64):
  Before uninstall, this module version was ACTIVE on this kernel.
  Deleting /lib/modules/7.0.0-15-generic/updates/dkms/hp-wmi.ko.zst
  Restoring archived original module /lib/modules/7.0.0-15-generic/kernel/drivers/platform/x86/hp/hp-wmi.ko.zst
  Running depmod... done.

Deleting module hp-wmi-fan-and-backlight-control/0.0.2 completely from the DKMS tree.
Creating symlink /var/lib/dkms/hp-wmi-fan-and-backlight-control/0.0.2/source -> /usr/src/hp-wmi-fan-and-backlight-control-0.0.2
Sign command: /usr/bin/kmodsign
Signing key: /var/lib/shim-signed/mok/MOK.priv
Public certificate (MOK): /var/lib/shim-signed/mok/MOK.der

Building module(s)... done.
Signing module /var/lib/dkms/hp-wmi-fan-and-backlight-control/0.0.2/build/hp-wmi.ko
Found pre-existing /lib/modules/7.0.0-15-generic/kernel/drivers/platform/x86/hp/hp-wmi.ko.zst, archiving for uninstallation
Installing /lib/modules/7.0.0-15-generic/updates/dkms/hp-wmi.ko.zst
Running depmod... done.
--> Reloading patched hp-wmi module...
Error: Patched hp_wmi fan target controls are missing under /sys/devices/platform/hp-wmi/hwmon/hwmon6.
Error: Patched hp_wmi fan target controls are missing under /sys/devices/platform/hp-wmi/hwmon/hwmon6.
Error: Patched hp_wmi fan target controls are missing under /sys/devices/platform/hp-wmi/hwmon/hwmon6.
selvatharrun@selvatharrun-Victus-by-HP-Laptop-16-d0xxx:~/victus-control$
"""