Kompas 0.1.0 preview 3 — no stray window, faster startup

Kompas 0.1.0 preview 3 — no stray window, faster startup

This preview fixes a stray window and a slow first search on Zorin.

• Kompas no longer leaves an empty "winit window" in the taskbar that could not be
  closed. iced's hidden start-up window is now destroyed once the real window opens.
• System package availability is cached on disk until the apt metadata changes.
  After the first start, the local catalog no longer waits several seconds for
  PackageKit to list all packages.
• Zorin's extra software catalog loads even though its header repeats a key.
• Flathub statistics download with timeouts, from a fixed release tag, and are
  only cached when they decode.
• Caches moved to ~/.cache/kompas. The old ~/.cache/cosmic-store can be deleted.
• Steam requests share one HTTP client; cached artwork is checked to be an image;
  cache files are written atomically.

Download kompas-preview-amd64.deb and SHA256SUMS. In that directory:

sha256sum -c SHA256SUMS
sudo apt install ./kompas-preview-amd64.deb
kompas

The package replaces the previous preview. Quit Kompas before opening the new version.
Tested by CI: formatting, clippy, workspace tests, package replacement, metadata,
X11 browsing, and that no bootstrap window remains. This is a stripped debug preview
for Zorin 18 / Ubuntu 24.04, Intel/AMD 64-bit.

Known limits: no signed APT channel for Kompas itself yet; no integrated Epic/GOG
catalog or user review system. Native Linux flags do not guarantee hardware,
Proton or anti-cheat compatibility.