v0.4.0

Portable Windows x64 build from 13dbd04a75d819b7a119a57e9d0e5a4a36efc37b.

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:

• fix(ci): stage release artifacts inside the workspace for upload-artifact (13dbd04)
• ci: single Windows job, tests moved to local push gate (096a9f6)
• feat: Enhance project structure and agent instructions (b9f4b17)