[core][flink][spark] Support ARRAY<BLOB> blob files

[leaves12138]

Purpose

Support storing top-level ARRAY columns in dedicated blob files, so one table can use blob file storage for both BLOB and ARRAY fields across core, Flink, and Spark paths.

Changes

• Treat BLOB and ARRAY as blob-file fields in schema validation, data-evolution planning, blob file context, and column directive cleanup.
• Extend BlobFileFormat reader/writer with an ARRAY payload layout that keeps one blob-file record per table row and stores per-element lengths in a compact tail index.
• Preserve support for null arrays, null elements, empty arrays, selection reads, descriptor reads, inline reads, and whole-field placeholders.
• Add Flink catalog conversion and Flink array read conversion so ARRAY blob fields round-trip as ARRAY internally.
• Add Spark catalog conversion and Spark array/data converters so ARRAY blob fields round-trip as ARRAY internally.
• Add format-level, table-level, Flink e2e, and Spark e2e coverage for ARRAY.

Tests

• JAVA_HOME=/opt/jdk-17.0.2.jdk/Contents/Home mvn -pl paimon-core,paimon-format -am -DskipTests compile
• JAVA_HOME=/opt/jdk-17.0.2.jdk/Contents/Home mvn -pl paimon-format -am -Pfast-build -DfailIfNoTests=false -Dtest=BlobFileFormatTest test
• JAVA_HOME=/opt/jdk-17.0.2.jdk/Contents/Home mvn -pl paimon-core -am -Pfast-build -DfailIfNoTests=false -Dtest=BlobTableTest#testArrayBlobField,ColumnDirectiveUtilsTest#testBlobDirectiveWithArraySourceType test
• JAVA_HOME=/opt/jdk-17.0.2.jdk/Contents/Home mvn -pl paimon-flink/paimon-flink-common -am -Pfast-build -DfailIfNoTests=false -Dtest=BlobTableITCase#testArrayBlobField test
• JAVA_HOME=/opt/jdk-17.0.2.jdk/Contents/Home mvn -pl paimon-api,paimon-format,paimon-core,paimon-bundle,paimon-spark/paimon-spark-common,paimon-spark/paimon-spark3-common -am -Pfast-build,spark3 -DskipTests install
• JAVA_HOME=/opt/jdk-17.0.2.jdk/Contents/Home mvn -pl paimon-spark/paimon-spark-ut -am -Pfast-build,spark3 -DfailIfNoTests=false -DwildcardSuites=org.apache.paimon.spark.sql.BlobTestBase -Dtest=none test

[JingsongLi]

Let's add Python together.