build(tags): reissue sure alpha in dedicated package

[JSONbored]

Summary

• reissue Sure alpha as 0.7.1-alpha.7-aio.5
• move alpha image metadata to the dedicated sure-aio-alpha package
• document the reduced alpha tag set

What changed

• sure-alpha now uses jsonbored/sure-aio-alpha for Docker Hub and GHCR
• alpha image tags are documented as latest-alpha plus the explicit AIO package tag
• alpha XML points at jsonbored/sure-aio-alpha:latest-alpha
• alpha AIO revision moves to 5 so the corrective publish does not retarget an immutable prerelease

Why

• 0.7.1-alpha.7-aio.4 was published under the stable package path
• the corrective publish needs a new immutable release tag and the dedicated alpha package path

Validation

• python -m pytest tests/test_alpha_lane_assets.py
• black --target-version py312 --check tests/test_alpha_lane_assets.py
• git diff --check

Notes

• an existing untracked local rootfs-alpha/...route_parity_importer.rb file was left untouched