v2.4 - H.265 & AV1 export

What's new

Export H.265 (HEVC) and AV1. Two new entries in the format dropdown —
MP4 (H.265) and MP4 (AV1) — for much smaller files at the same quality:

• H.265 uses your GPU (hevc_nvenc) when Fast encode is on, or libx265
  on the CPU. Tagged hvc1 so the MP4s play in QuickTime, Windows, and on Apple
  devices.
• AV1 uses av1_nvenc on RTX 40-series GPUs (detected automatically), or the
  libsvtav1 CPU encoder everywhere else — an AV1 export never fails for lack of
  hardware.

Tidier Export tab. It now shows only the controls that apply to the chosen
format — fast-trim and target-size appear for H.264, the GPU toggle drops off for
WebM/GIF, and GIF swaps the quality slider for an fps spinner.

Downloads

• Windows installer — Leike-Setup.exe (ffmpeg bundled; per-user, no admin
  prompt).
• Windows portable — Leike-portable-win64.zip (unzip and run; ffmpeg
  bundled).
• Windows standalone — Leike.exe (drop an ffmpeg.exe beside it, or use
  the installer / portable).
• macOS (Apple Silicon) — Leike-macOS-arm64.zip (brew install ffmpeg
  first; first launch: right-click → Open).
• Linux (x86_64) — Leike-linux-x86_64.tar.gz (install ffmpeg with your
  package manager).