Docker Hub floating tags (latest, 8, 8.0) are stale — stuck at 8.0.1

## Description

The Docker Hub floating tags for `owncloud/ocis` have not been updated to track the latest releases:

| Tag | Points to | Last updated |
|-----|-----------|-------------|
| `latest` | 8.0.1 | 2026-03-11 |
| `8` | 8.0.1 | 2026-03-11 |
| `8.0` | 8.0.1 | 2026-03-11 |
| `8.0.3` | 8.0.3 | 2026-05-11 |
| `8.0.2` | 8.0.2 | 2026-05-11 |

The versioned tags `8.0.2` and `8.0.3` were pushed to Docker Hub, but `latest`, `8`, and `8.0` were not moved to point to them.

## Impact

Users relying on `owncloud/ocis:latest` (or `:8`, `:8.0`) are stuck on 8.0.1 and miss the 8.0.2 and 8.0.3 releases. Automated updaters like Watchtower won't detect the new versions since the floating tags appear unchanged.

## Expected

`latest`, `8`, and `8.0` should point to the latest stable release (currently 8.0.3).

Also, the `8.0.3` image binary reports version `8.0.2+af145c25` internally (`ocis version`), which may be a separate build-time version-string issue.