docs(changelog): LayoutDecoder SPI

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: dfa1

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `Compute.filteredSum(filterColumn, predicate, aggColumn)` fuses a filter and a sum into a single scan — a row folds into the total only when the predicate selects it (a null filter row is excluded) and the aggregate value is non-null — with no intermediate selection bitmap. It matches a hand-written fused loop and is ~1.5× faster than the two-pass `filter` + `sum`. ([57d2225b](https://github.com/dfa1/vortex-java/commit/57d2225b))
 - `Compute.filteredAggregate(chunk, filter, aggColumn)` fuses a whole multi-column `RowFilter` (an n-ary `AND` of column-bound predicate leaves) and folds the selected rows' `SUM`/`MIN`/`MAX`/non-null count over an aggregate column in a single pass — the multi-column counterpart of `filteredSum`, and the row-level kernel behind the Calcite boundary-chunk aggregate push-down. A `null` aggregate column counts selected rows only (`COUNT(*)`). ([2ba54888](https://github.com/dfa1/vortex-java/commit/2ba54888))
 - `core.model.LayoutId` — typed layout identity with the same sealed shape as `EncodingId` (`WellKnown` constants plus `Custom`; layouts are runtime-pluggable in the reference implementation). The reader now recognizes `vortex.zoned`, the current canonical zone-map layout id in the Rust reference, alongside the legacy `vortex.stats` alias it keeps writing — files from current Rust writers scan and prune correctly. ([7df3a0db](https://github.com/dfa1/vortex-java/commit/7df3a0db))
+- Layout decode is pluggable: `LayoutDecoder` + `LayoutRegistry` (`reader.layout`) mirror the encoding registry — `LayoutRegistry.builder().registerDefaults().register(custom).build()` passed to the new `VortexReader.open(path, readRegistry, layoutRegistry)` / `VortexHttpReader` overloads dispatches every layout decode, container children included, through the registry. Programmatic registration only (no service file); unknown layouts fail loudly. Zone-map pruning and filtered scans recognize the built-in layouts only. ([fc488d04](https://github.com/dfa1/vortex-java/commit/fc488d04), [dd196f17](https://github.com/dfa1/vortex-java/commit/dd196f17))
 
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