[Subtask] Add Trino 481 version-segment module

### Describe the subtask

Add `trino-connector-481-481` (JDK 25 toolchain), depending on the shared
version seam (#).

Trino 481 adds (on top of 480): `ConnectorMetadata.finishTableExecute`
return type changes `void` -> `Map`, handled in the
per-version `GravitinoMetadata481` wrapper.

Includes: module wiring, unit test (TestGravitinoConnector481), and
docs/compat-matrix updates.

### Parent issue

https://github.com/apache/gravitino/issues/12632

Start by examining the existing Trino 480 version module and the shared version seam referenced by #, then compare the per-version metadata wrapper behavior. Add the 481 module wiring and JDK 25 toolchain, cover it with TestGravitinoConnector481, and update docs/compat-matrix; done means the 481 connector builds and the unit test passes.

Written by the indexing model from the issue text.