Polaris persistence / unclear behavior when creating entites with the same name

### Describe the bug

I'm not sure whether Polaris persistence can ensure that no two entities (think: Iceberg tables & views) with the same name can ever exist.

The reason I'm bringing this up is the disconnect of the name resolution vs technical ID resolution.

It feels possible that two concurrent requests to e.g. create a new table pass the "that name does not yet exist" check and then both write new entities with the same name.

The name checks are only _programmatic_ checks against previous read operations - but there is nothing that technically prevents having duplicate names.

### To Reproduce

_No response_

### Actual Behavior

_No response_

### Expected Behavior

_No response_

### Additional context

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### System information

_No response_

No files, tests, or entry points are named. Start by tracing Polaris persistence creation and the separate name- and technical-ID-resolution paths, then examine concurrent creation of entities with the same name. Done requires a documented uniqueness decision and verification of the resulting behavior under concurrent requests.

Written by the indexing model from the issue text.