v0.5.0 — H11 hardware encode promotion

H11 — Auto-promote software encoding to GPU. Exports that would use the slow software encoder (libopenh264) are now auto-redirected to an available hardware encoder (NVENC/QSV) — for the ~13% of exports on machines where no GPU encoder was selected. Fail-safe fallback to software, no quality loss (SSIM ≥ 0.99). MC 1.21.9/1.21.10/1.21.11, Java 21.