feat: add sink.parallelism support for OceanBase JDBC connector

[yuanoOo]

Summary

• Add support for configuring sink parallelism via sink.parallelism option in SQL DDL or Table Hints
• Users can now set a custom parallelism for the sink operator

Changes

• Add SINK_PARALLELISM config option in ConnectorOptions
• Modify SinkProvider to support parallelism via getParallelism() method
• Register the option in OceanBaseDynamicTableSinkFactory
• Pass parallelism parameter in OceanBaseDynamicTableSink
• Add unit test for SinkProvider parallelism
• Add integration test for sink.parallelism configuration

Usage

DDL Configuration

CREATE TABLE ob_sink (
    id INT,
    name STRING
) WITH (
    'connector' = 'oceanbase',
    'url' = 'jdbc:mysql://localhost:2881/test',
    'username' = 'root',
    'password' = 'password',
    'schema-name' = 'test',
    'table-name' = 'sink_table',
    'sink.parallelism' = '4'
);

Table Hints

INSERT INTO ob_sink /*+ OPTIONS('sink.parallelism' = '8') */
SELECT * FROM source_table;

Test Plan

• Unit test: AbstractDynamicTableSinkTest verifies getParallelism() returns correct value
• Integration test: testSinkParallelism in OceanBaseMySQLConnectorITCase
• GitHub CI passes