py_func, lua_func and the run item now reach host binaries through
`flatpak-spawn --host` instead of trying to load them under the
sandbox runtime (which fails with a glibc ABI mismatch). Adds
`--talk-name=org.freedesktop.Flatpak` to the manifest, stages the
/app/lib/testium tree under /tmp so the host can read it, and drops
the dead `_FLATPAK_HOST_DIRS` / lib-injection code paths that the
new approach makes obsolete.
Validation suite gains a `--mode source|wheel|pyinstaller|flatpak|
appimage` flag so the same item set can run against every packaging
channel; per-mode report file names avoid clobbering.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
org.testium.Testium.yaml uses host Python/Lua only (no bundled interpreter).
build.sh exports a .flatpak bundle. README documents the install procedure.
