Strip half-bundled crypto/print libraries from the AppImage

[rlnorthcutt]

linuxdeploy bundles libgcrypt.so.20 (pulled in transitively by
webkit2gtk) but not its version-locked pair libgpg-error.so.0 -- the
latter is on linuxdeploy's own built-in exclude list, the former isn't,
even though upstream GnuPG always releases the two version-locked
together. Bundling one without the other means the bundled libgcrypt
(built against the build machine's libgpg-error) loads against
whatever libgpg-error the run machine provides instead. Confirmed the
hard way: a Fedora-built AppImage crashed at launch on Ubuntu with
"undefined symbol: gpgrt_add_post_log_func, version GPG_ERROR_1.0" --
the exact inverse of the earlier EGL bug (that one broke on some
hardware when built on Ubuntu; this one breaks on Ubuntu when built on
Fedora), confirming the fix needs to be "exclude the library properly,"
not "pick a different distro to build on."

Swept every other bundled library's own dependencies against
linuxdeploy's real exclude list for the same half-bundled-pair
pattern; found one more, lower severity: libprintbackend-cups.so (a
GTK print plugin, not a startup dependency) needs avahi/colord/cups,
none of which are bundled or excluded either.

Add scripts/strip-unsafe-appimage-libs.sh -- a post-build step that
extracts the built AppImage, removes both, and repackages via the same
linuxdeploy-plugin-appimage tauri itself already downloads. Wired into
both scripts/build-appimage.sh (local) and npm run build:linux (CI).
Verified end-to-end through both paths, including the real Fedora
container CI uses, with a cold plugin cache. Deliberately not fixed by
shipping separate Ubuntu/Fedora AppImages -- that shifts the "which one
do I download" problem onto users without guaranteeing correctness on
a third distro.

Bump to 0.5.0-alpha.9.