Support Apache Paimon as a first class citizen in the catalog.

### Is your feature request related to a problem? Please describe.

I realise there is going to be allot of we need to do this, they need to do that.

As a user... I honestly don't care, I want one catalog service, that contains all my catalogs with all my databases.
one catalog being iceberg
one catalog being paimon
and ye, one catalog being hudi...
and maybe even more eventually...
i'd love to plug into Apache Fluss catalog store also.
Allowing the user to have one service... "REST" based that contains references to all my data products...
G

### Describe the solution you'd like

_No response_

### Describe alternatives you've considered

_No response_

### Additional context

_No response_

The request names Apache Paimon, Iceberg, Hudi, and a REST-based unified catalog, but it does not identify files, entry points, tests, or acceptance criteria. Start by reviewing the existing catalog integration architecture and clarify the compatibility and API scope for Paimon before defining what a complete implementation would require.

Written by the indexing model from the issue text.