fix: convert primitives to Objects inside of WebChunkReaderFactory

[nbauernfeind]

Fixes #6201.

PR Overview

This pull request fixes issue #6201 by converting primitives to objects in the web client’s Barrage API. Key changes include:

• Consolidation of column data handling into a single concrete WebColumnData class with new implementations for fillFromChunk and applyUpdate.
• Refactoring of WebChunkReaderFactory to use new helper methods (e.g. newIntReader, newFloatReader) that convert primitive chunks into WritableObjectChunk instances.
• Removal of auto‐generated, primitive-specific column data classes in favor of a unified object‐based approach.

Reviewed Changes

File	Description
web/client-api/src/main/java/io/deephaven/web/client/api/barrage/data/WebColumnData.java	Converted from abstract to concrete class and added object–based update logic.
web/client-api/src/main/java/io/deephaven/web/client/api/barrage/WebChunkReaderFactory.java	Introduced new helper methods to simplify primitive to object conversion.
web/client-api/src/test/java/io/deephaven/web/client/api/HierarchicalTableTestGwt.java	Re-enabled the DISTINCT aggregation to reflect the updated conversion logic.
Other files	Adjustments throughout the subscription and state layers to accommodate the changes above.

Copilot reviewed 17 out of 17 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (3)

web/client-api/src/main/java/io/deephaven/web/client/api/barrage/WebChunkReaderFactory.java:389

• [nitpick] Ensure that the new newIntReader implementation is adequately covered by tests, particularly for edge cases such as unsigned 64-bit integers and varying input sizes.

throw new IllegalArgumentException("Unsigned 64bit integers not supported");

web/client-api/src/main/java/io/deephaven/web/client/api/barrage/WebBarrageMessageReader.java:125

• [nitpick] Review the decision to instantiate all chunks using WritableObjectChunk to ensure that the conversion from primitives does not lead to unintended type conversion issues for expected primitive values.

final WritableChunk<Values> chunk = WritableObjectChunk.makeWritableChunk(chunkSize);

web/client-api/src/test/java/io/deephaven/web/client/api/HierarchicalTableTestGwt.java:372

• [nitpick] After re-enabling the DISTINCT aggregation, confirm that tests adequately cover scenarios involving DISTINCT operations to prevent regression issues.

JsAggregationOperation.DISTINCT,