feat(predator): add PHN16-72 back logo/lightbar controls

[0PeterAdel]

Summary

Adds safe, static rear back-logo/lightbar control to DAMX when the Linuwu-Sense driver advertises the back_logo capability.

The GUI exposes the hardware-backed controls supported by the driver: RGB color, brightness, enable/disable, and Apply.

Fixes #198.

Changes

• Detects the driver-provided back_logo/color sysfs capability.
• Adds back_logo to daemon feature discovery and back_logo_color to get_all_settings.
• Adds the set_back_logo_color daemon command.
• Adds DAMXClient.SetBackLogoColorAsync.
• Adds a Back Logo / Lightbar card under Keyboard Lighting.
• Strictly validates RGB, brightness, and boolean enable values before any sysfs write.
• Preserves a useful GUI brightness when disabled firmware readback is normalized to RRGGBB,0,0.
• Limits this integration to static writes; continuous software effects were deliberately removed to avoid repeatedly invoking the firmware WMI setter.

Driver dependency

Requires PXDiv/Div-Linuwu-Sense#20, which exposes:

/sys/module/linuwu_sense/drivers/platform:acer-wmi/acer-wmi/back_logo/color

Format:

RRGGBB,brightness,enable

Validation

Validated at commit b8f9cb13d8b2b349a44dfd38fbc2e2d632eda805 on:

• Acer Predator PHN16-72 / EQE_RTX
• BIOS V1.16
• Omarchy
• Linux 7.1.9-arch1-2
• .NET SDK 9.0.120

Results

• Python syntax check passed.
• Release build passed with 0 errors.
• Warning regression comparison: 95 baseline warning types, 95 PR warning types, 0 introduced by this PR.
• Strict daemon validation passed 10/10 valid and malformed-input cases.
• End-to-end socket -> daemon -> sysfs test passed.
• Invalid API input was rejected without changing hardware state.
• GUI successfully applied #00FFCC at 40% brightness.
• GUI disable state and physical logo-off state were verified.
• No relevant kernel faults or critical GUI runtime errors were logged.
• Original logo state and installed DAMX service were restored after testing.

Safety

Only one Acer WMI driver should be loaded at a time. This integration was tested with the patched linuwu_sense module from the linked driver PR.

[0PeterAdel]

Hardware validation evidence

Validated commit b8f9cb13d8b2b349a44dfd38fbc2e2d632eda805 on:

• Acer Predator PHN16-72 / EQE_RTX
• BIOS V1.16
• Omarchy
• Linux 7.1.9-arch1-2
• .NET SDK 9.0.120

Test results

Check	Result
Python syntax check	PASS
Release build	PASS — 0 errors
Warning regression	PASS — 95 baseline vs. 95 PR warning types; 0 introduced
Strict daemon validation	PASS — 10/10 cases
Socket → daemon → sysfs path	PASS
Invalid-input state preservation	PASS
GUI static color and brightness	PASS — #00FFCC at 40%
GUI and physical disable state	PASS
Critical GUI runtime errors	None logged
Relevant kernel faults	None logged
Service and hardware rollback	PASS

Invalid RGB, brightness, and enable values were rejected without modifying the hardware state. The GUI successfully controlled the physical rear logo through the PR daemon and the driver sysfs interface.

1. GUI — enabled with Cyan #00FFCC at 40%

2. Physical hardware — Cyan output

3. GUI — disabled while retaining the 40% selection

4. Physical hardware — logo disabled

5. Final rollback evidence

After testing, the original logo state dff8ff,100,1 and the installed damx-daemon.service were restored successfully.

[0PeterAdel]

Hi @PXDiv, gentle review ping when you have time.

I could not find a CONTRIBUTING.md or CODEOWNERS file here, so I am following the README guidance and keeping the update in the PR. This PR implements the app/daemon side of the PHN16-72 rear logo request in #198 and depends on the driver support in PXDiv/Div-Linuwu-Sense#20.

Current status:

• Mergeable, with no unresolved review threads.
• Real PHN16-72 hardware validation and screenshots are posted above.
• Static-only control: RGB color, brightness, enable/disable, and Apply.
• Invalid RGB/brightness/enable inputs are rejected before sysfs writes.
• Continuous software effects were deliberately left out to avoid repeated firmware WMI writes.

If you would rather merge the driver side first, I can rebase or adjust this PR after PXDiv/Div-Linuwu-Sense#20 lands.