feat(devices): add Logitech Signature M650

[abdallah-azzouni]

Adds device descriptor for the Logitech Signature M650 (PID 0xb02a).

Verified on hardware via Bolt receiver on Linux (Nobara/Fedora).

Features confirmed via Solaar:

• Battery: UNIFIED BATTERY {1004} ✓
• Adjustable DPI: {2201}, range 400–4000, step 100 ✓
• Reprogrammable controls: REPROG CONTROLS V4 {1B04} ✓
• Low-res wheel: LOWRES WHEEL {2130} ✓
• No SmartShift, no HiRes wheel, no thumb wheel, no gesture button

Controls (CIDs from live device):

• Left/Right click (non-configurable)
• Middle click, Back, Forward (configurable)

Status set to beta pending maintainer verification.
All 737 tests pass.

[Copilot]

Pull request overview

Adds support metadata for the Logitech Signature M650 (PID 0xb02a) by introducing a new device descriptor and registering it in the test/device listing surfaces.

Changes:

• Add new devices/m650/descriptor.json descriptor (plus images) defining features, DPI range, controls, and hotspots for “Signature M650”.
• Extend the device registry test matrix (kDevices[]) to include “Signature M650” coverage.
• Add “Signature M650” to the Supported Devices table in README.md.

Reviewed changes

Copilot reviewed 3 out of 6 changed files in this pull request and generated 1 comment.

File	Description
tests/test_device_registry.cpp	Adds a new DeviceSpec entry for “Signature M650” and reformats the file.
devices/m650/descriptor.json	Introduces the Signature M650 descriptor (features/DPI/controls/hotspots/images).
README.md	Adds Signature M650 row to the supported devices table.

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[Copilot]

Pull request overview

Adds a new device descriptor to support the Logitech Signature M650 (PID 0xb02a) within the existing JSON-driven device registry, along with registry tests and README documentation updates.

Changes:

• Added devices/signature-m650/descriptor.json (plus referenced images) describing features, controls, hotspots, and DPI range for the Signature M650.
• Extended tests/test_device_registry.cpp coverage by registering the new PID/name/spec expectations.
• Updated the Supported Devices table in README.md to include Signature M650 (Beta).

Reviewed changes

Copilot reviewed 3 out of 6 changed files in this pull request and generated 2 comments.

File	Description
tests/test_device_registry.cpp	Adds a DeviceSpec entry for PID 0xb02a to validate registry loading and key descriptor properties.
devices/signature-m650/descriptor.json	Introduces the Signature M650 device descriptor (features/DPI/controls/hotspots/images).
README.md	Documents the Signature M650 as a supported (Beta) device in the devices table.

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[mmaher88]

@abdallah-azzouni Thanks for this — the descriptor is in good shape and I validated it end to end before reviewing: rebases cleanly onto master, builds, 737/737 C++ + 9/9 tray tests pass, and both generate-readme-devices.py --check and generate_package_deps.py --check are green. The DeviceSpec entry is present (pid 0xb02a, matching productIds) and covered by the AllDevices instantiation, the three images are valid, and I cross-checked the feature flags against Logitech's published M650 specs — smartShift: false, thumbWheel: false, adjustableDpi with a 400–4000 range, and lowResWheel: true / hiResWheel: false all look right for this tier of mouse.

One change needed before merge:

devices/signature-m650/descriptor.json sets "gestureButton": false inside features, but that key doesn't exist in devices/schema.json. The features object is additionalProperties: false, so the descriptor is not schema-conformant. It's also never parsed — grep for gestureButton in src/core/devices/JsonDevice.cpp turns up nothing, so it's inert JSON rather than a functional bug.

Please either:

• drop the key (simplest — the M650 has no gesture button, and omitting a flag already means "unsupported"), or
• rename it to mouseGesture, which is the real, parsed flag, if you meant to declare it explicitly as false.

For reference, the schema's allowed features keys are: adjustableDpi, angleSnapping, battery, colorLedEffects, crown, extendedDpi, extendedReportRate, forceSensingButton, gestureV2, gkey, hapticFeedback, hiResScrolling, hiResWheel, leftRightSwap, lowResWheel, mkeys, mouseGesture, onboardProfiles, persistentRemappableAction, pointerSpeed, reportRate, reprogControls, rgbEffects, smartShift, smoothScroll, surfaceTuning, thumbWheel.

Worth noting this is our gap as much as yours: CI doesn't currently validate descriptors against schema.json, so nothing flagged it automatically. I'm tracking that as a separate improvement.

Once that key is fixed this is good to merge — no code changes needed, it's a clean descriptor-only addition exactly as the capability-dispatch architecture intends. Thanks for contributing a device!

[abdallah-azzouni]

@mmaher88 Thanks for the thorough review. I removed the gestureButton key from descriptor.json. it's not in the schema and wasn't being parsed anywhere, so dropping it was the simplest fix. Should be schema-conformant now and ready for another look.