HDR to SDR v3.1.5

What's new

Real 3D LUT color pipeline: color conversion now runs through a proper BT.2020→BT.709 3D LUT on both the CPU and GPU tonemapping paths, replacing the previous approximate gamut math with more accurate color reproduction.
"Accurate GPU Color" is now a permanent per-batch-item setting, and it now applies to every tonemapper instead of only GPU-only ones.
Improved logging: rate-limited error logging, a persistent log file, and clearer warnings.
The app now notifies you when a Dolby Vision profile 5 source overrides the GPU toggle.

Fixed preview accuracy bugs where the GPU preview cache could serve stale or incorrect frames (prewarm cache poisoning and cache-key mismatches).
The CPU LUT filter now uses tetrahedral interpolation for smoother color results.
Corrected the LUT generator's transfer curve and grid resolution.
Fixed LUT filter path handling so paths containing backslashes on Windows no longer break the filter.
Improved tooltip text for GPU export color correction options.

Full Changelog: v3.1.4...v3.1.5