feat: tablechunks can reconstruct table (#4291)
<!-- CURSOR_SUMMARY -->
> [!NOTE]
> **Medium Risk**
> Changes core table-chunking behavior by adding new metadata fields and
reconstruction logic; risk is mainly around backward compatibility and
correct ordering/HTML merging of split tables.
>
> **Overview**
> Adds end-to-end support for reassembling split tables after chunking.
`TableChunk` now receives stable sequencing metadata (`table_id`,
`chunk_index`) when a `Table` is split, and a new
`reconstruct_table_from_chunks()` helper in
`unstructured.chunking.dispatch` groups and merges `TableChunk`s back
into full `Table` elements (including merged `text_as_html` when
available).
>
> Updates `ElementMetadata` to carry the new fields (dropped during
consolidation), bumps version to `0.22.4`, and adds unit tests covering
reconstruction across mixed element streams and edge cases like missing
`chunk_index`.
>
> <sup>Written by [Cursor
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1e732a3e366d6f3f93c898ad2e5e9944855bf0fa. This will update automatically
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<!-- /CURSOR_SUMMARY -->
---------
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: cragwolfe <crag@unstructured.io>
