* fix(aur): gate source publication on attested sdists
Prepare and verify the canonical release source, build the exact PKGBUILD on Arch, and publish the gated artifact without further rewrites. Part of #701.
* fix(aur): isolate local gate and binary publication
Keep local gate distributions and diagnostics in a private workspace, preserving other build outputs and failed diagnostics. Publish vocalinux-bin after its own AppImage inputs without depending on the source gate or unrelated release jobs. Add regression coverage for both review findings.
