ci(sync): centralize catalog automation

[JSONbored]

Summary

• keep awesome-unraid as the catalog asset repo while moving local automation logic into aio-fleet

What changed

• removes the catalog-local changelog workflow and git-cliff config
• removes the local README inventory validator script
• updates validate-catalog to run centralized aio-fleet validate and audit commands pinned to the merged control-plane commit
• regenerates CHANGELOG.md with the centralized catalog changelog command

Why

• aio-fleet is the shared control plane for fleet automation, and awesome-unraid should only carry the final catalog XML, icons, screenshots, README, and CHANGELOG.md assets.

Validation

• python -m aio_fleet validate-catalog --catalog-path .
• python -m aio_fleet catalog-audit --catalog-path .
• python -m aio_fleet catalog-changelog --catalog-path . --check
• python -m aio_fleet catalog-workflow --catalog-path . --aio-fleet-ref f5bc53e7e34b86630173a3e1e4c0e5148c468cbd --check
• git diff --check