CI and PWM fixes

[freezy]

• CI builds properly again
• PinMAME's PWM implementation switched to a float array, so this PR updates that as well (it's currently converted linearly to gray8).
• Identification frames are more explicit (sorry that's pretty all I can remember).

[Copilot]

Pull request overview

This pull request addresses CI build issues and updates PinMAME's PWM implementation to use a float array instead of byte array for luminance data, along with improving identification frame handling.

Key Changes:

• PWM implementation now uses float arrays for luminance data with linear conversion to grayscale
• Identification frames are handled more explicitly with the NeedsIdentificationFrames property added to all destination implementations
• CI workflow improved with per-branch build numbering

Reviewed changes

Copilot reviewed 32 out of 36 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
PinMameDevice/DmdDevice.cs	Updated PWM rendering to accept float luminance data and convert to bytes
LibDmd/RenderGraph.cs	Updated frame subscription logic to respect identification frame requirements
LibDmd/Output/IDestination.cs	Added NeedsIdentificationFrames property to interface
LibDmd/Output/**/*.cs	Implemented NeedsIdentificationFrames property across all output devices
LibDmd/Frame/DmdFrame.cs	Made IsIdentifyFrame property private and added DataHash method
LibDmd/DmdDevice/DmdDevice.cs	Fixed SetColor bug and updated logging configuration
LibDmd/Common/InteropUtil.cs	Changed to static class and added ReadByteArray method
LibDmd/Common/Profiler.cs	Improved DEBUG conditional compilation
.github/workflows/build.yml	Added per-branch build number computation

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[Copilot]

The variable 'uint16Buffer' is misleadingly named since it's declared as a byte array. Consider renaming to 'byteBuffer' or 'rawBytes' to accurately reflect its type.