Support CREATE TABLE with namespace integration

[jackye1995]

to create the lance table in a proper catalog not just locally

[fightBoxing]

Regarding the points you raised, I have improved and supplemented the code and added unit tests.

the commitId: 4473c31

[fightBoxing]

Confirmed implemented on upstream/main (HEAD ffe4fc0, i.e. after PR #52).

LanceNamespaceCatalog routes all table DDL through the official
org.lance.namespace.LanceNamespace API — the exact "in a proper catalog
not just locally" behavior this issue asks for:

• createTable → namespace.createTable(CreateTableRequest) (L323)
• dropTable → namespace.dropTable(DropTableRequest) (L354)
• tableExists → namespace.tableExists(TableExistsRequest) (L280)
• getTable → namespace.describeTable(DescribeTableRequest) (L293)
• listTables → namespace.listTables(ListTablesRequest) (L247)

End-to-end test: LanceNamespaceCatalogITCase#testCreateTable runs against
a real DirectoryNamespace, asserting createTable → tableExists →
listTables all succeed.

Landing commit: 58ca6cd (via PR #52). Safe to close.