🐞 Throw an error if manifest contains sequence_order of zero

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

If the manifest contains any zero sequence_orders then it allows them through, but that fails later in the process.

### Expected Behavior

_No response_

### Steps To Reproduce

_No response_

### Environment

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- OS:
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### Anything else?

_No response_

No file or test is named. Start by locating the manifest parsing and validation entry point, then trace how sequence_order values are handled. Add coverage for a zero value and verify that manifests containing one are rejected before later processing.

Written by the indexing model from the issue text.