v0.5.0

Portable Windows x64 build from cb3b223f5b38e952390e33fed2ae1c88afed165e.

Extract the complete ZIP and run SteamVRColourLab.exe; Python is bundled.

Validation: automated tests with Mesa software rendering, Windows package integrity, and relocated executable startup. Headset behavior requires separate runtime testing.

Changes since the previous version:

• feat: Implement bitrate workload management and associated tests (cb3b223)
• docs(skill): record the workspace artifact staging rule (09681e9)
• docs: record CI timings, artifact staging fix and local gate (820ab94)