feat: add Apache Pinot OFFLINE segment sink connector

[deeppatel710]

Summary

• Adds a pinot Flink SQL connector that writes RowData into Apache Pinot OFFLINE segments using FlinkSegmentWriter + SegmentUploaderDefault from pinot-flink-connector 1.3.0 (no SNAPSHOT required)
• At-least-once delivery: segments flush on every Flink checkpoint and when segment.flush.rows threshold is reached; async upload via a small executor pool
• Supports all Flink SQL primitive types, TIMESTAMP_LTZ (→ epoch millis), and DECIMAL (→ double)

New files

File	Purpose
PinotDynamicTableFactory	Registers 'connector' = 'pinot'; options: controller.url, table.name, segment.flush.rows
PinotDynamicTableSink	Bridges DynamicTableSink → PinotRowDataSink
PinotRowDataSink	Flink 2.x Sink<RowData> with async segment upload
PinotRowDataConverter	Maps Flink RowData fields to Pinot GenericRow
PinotOptions	Typed connector option constants

Example DDL

CREATE TABLE my_pinot_table (
  user_id  BIGINT,
  action   STRING,
  event_ts TIMESTAMP_LTZ(3)
) WITH (
  'connector'          = 'pinot',
  'controller.url'     = 'http://pinot-controller:9000',
  'table.name'         = 'my_pinot_table',
  'segment.flush.rows' = '500000'
);

Dependency fixes (pom.xml)

• Calcite conflict: excluded org.apache.calcite:* from pinot-flink-connector so Flink 2.2's newer Calcite (which adds SqlTypeName.VARIANT) wins
• Jackson conflict: pinned jackson-core 2.18.2 — helix-core 1.3.1 otherwise pulls in 2.12.6, which is missing StreamReadConstraints needed by jackson-databind 2.18.2
• Chronicle Core / JDK 17+: added --add-opens argLine to Surefire for net.openhft:chronicle-core reflective JDK-internal access

Test plan

• PinotRowDataConverterTest — 5 unit tests covering primitives, TIMESTAMP_LTZ, DECIMAL, nulls, and post-deserialization behaviour
• PinotSinkFlinkTest.writesRowsToOfflineTable — end-to-end integration test: Flink minicluster + 4 Testcontainers (ZooKeeper + Controller + Broker + Server); generates 20 rows via datagen, inserts into Pinot OFFLINE table, asserts segment appears in controller REST API

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