[Feature](mongodb-cdc) Expose split-related CDC options for MongoDB

Expose additional MongoDB CDC source options that were previously not
configurable in mongodb-sync-database:

- scan.incremental.snapshot.chunk.size.mb
- scan.incremental.snapshot.chunk.samples
- split.meta.group.size
- close.idle.readers
- scan.full-changelog
- scan.cursor.no-timeout

These options allow users to control snapshot chunk granularity and
reader behavior, which is especially useful for large collections.

Author: ziyanTOP

flink-doris-connector/flink-doris-connector-flink1/src/main/java/org/apache/doris/flink/tools/cdc/mongodb/MongoDBDatabaseSync.java

@@ -86,6 +86,18 @@ public class MongoDBDatabaseSync extends DatabaseSync {
                     .noDefaultValue()
                     .withDescription("Table name of the Mongo database to monitor.");
 
+    public static final ConfigOption<Integer> SPLIT_META_GROUP_SIZE =
+            ConfigOptions.key("split.meta.group.size")
+                    .intType()
+                    .noDefaultValue()
+                    .withDescription("The meta group size of split.");
+
+    public static final ConfigOption<Boolean> CLOSE_IDLE_READERS =
+            ConfigOptions.key("close.idle.readers")
+                    .booleanType()
+                    .defaultValue(false)
+                    .withDescription("Whether to close idle readers.");
+
     public MongoDBDatabaseSync() throws SQLException {}
 
     @Override
@@ -222,6 +234,19 @@ public DataStreamSource<String> buildCdcSource(StreamExecutionEnvironment env) {
             default:
                 throw new IllegalArgumentException("Unsupported startup mode: " + startupMode);
         }
+
+        config.getOptional(MongoDBSourceOptions.SCAN_INCREMENTAL_SNAPSHOT_CHUNK_SIZE_MB)
+                .ifPresent(mongoDBSourceBuilder::splitSizeMB);
+        config.getOptional(MongoDBSourceOptions.SCAN_INCREMENTAL_SNAPSHOT_CHUNK_SAMPLES)
+                .ifPresent(mongoDBSourceBuilder::samplesPerChunk);
+        config.getOptional(SPLIT_META_GROUP_SIZE).ifPresent(mongoDBSourceBuilder::splitMetaGroupSize);
+        config.getOptional(CLOSE_IDLE_READERS)
+                .ifPresent(mongoDBSourceBuilder::closeIdleReaders);
+        config.getOptional(MongoDBSourceOptions.FULL_DOCUMENT_PRE_POST_IMAGE)
+                .ifPresent(mongoDBSourceBuilder::scanFullChangelog);
+        config.getOptional(MongoDBSourceOptions.SCAN_NO_CURSOR_TIMEOUT)
+                .ifPresent(mongoDBSourceBuilder::disableCursorTimeout);
+
         MongoDBSource<String> mongoDBSource = mongoDBSourceBuilder.deserializer(schema).build();
         return env.fromSource(mongoDBSource, WatermarkStrategy.noWatermarks(), "MongoDB Source");
     }