MoveBit v0.0.5

v0.0.5 — the desktop-fusion slice

Mubi melts into the desktop on every platform: Windows renders the
character through a GDI+ layered window (per-pixel alpha, click-through
for free), Linux drops the card and clears its opaque region, and the
header bar reaches title-bar parity with the mac host. History shard
writes gain a two-writer concurrency fix, and the Linux host builds
warning-free again. Flatpak sandbox execution is verified in CI on
both architectures.