DataFusion: paimon_incremental_query table function #506

Describe the feature

Expose batch incremental reads in DataFusion SQL via a table function, roughly:

SELECT * FROM paimon_incremental_query(
 'table_name',
 start_snapshot_exclusive,
 end_snapshot_inclusive
 [, 'auto' | 'delta' | 'changelog' | 'diff']
);

Also support the $audit_log style suffix so row kinds show up as a first column when needed.

Motivation

The Rust core incremental API is useful, but most people will want to poke at this from SQL. DataFusion should only parse args and adapt the execution plan — snapshot planning stays in paimon core.

Depends on

Core incremental Delta / Changelog / Diff support landing first (or the PR can sit on top of that stack).

Out of scope

• Reimplementing snapshot planning inside the DataFusion crate
• Lookup/compact changelog generation