Fix Oboe audio build error and optimize for "near-zero" latency

[google-labs-jules]

This PR addresses the build error and audio duplication issues reported with the Oboe audio redirection.

Key changes:

• Fixed "Unboxing a possibly null value" error in OboeAudioRedirector.cs by using safe pattern matching (is int h ? h : 0) for reflection-based handle retrieval.
• Optimized the C# mixing loop with System.Numerics.Vector<float> (SIMD) to achieve near-zero processing overhead in the audio path.
• Implemented CPU affinity in oboe_bridge.cpp to pin the audio callback thread to high-performance/exclusive cores, significantly reducing latency jitter.
• Fixed duplicated audio by cleanly switching BASS mixers to the "No Sound" device (Device 0) when Oboe is active. This silences the default BASS output path without using hacky volume mutes.
• Improved lifecycle management in OsuGameAndroid.cs to ensure BASS devices are correctly restored when Oboe is disabled.

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PR created automatically by Jules for task 8255708055978411559 started by @winnerspiros

[google-labs-jules]

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