Fix run-end slice export and generic decoding - #11375

## Summary

Builds on #11375.

Exporting a versioned Vortex UUID to Arrow and importing it back
currently drops the declared version, even when every value is
unchanged. Nested extensions can also lose metadata or fail to import
when Arrow fields disagree with their storage. The full dtype, including
nested metadata and nullability, must survive this round trip.

The raw import and export traits leave metadata transport to each
plugin. `ArrowExtVTable` puts that handling behind a typed registration
adapter, so extension authors implement their native conversions while
shared code preserves Vortex metadata.

## Changes

The session checks that inferred fields reconstruct the complete source
dtype and that successful plugin imports return the dtype inferred from
their field. These checks apply to raw and typed plugins. Explicit
export targets can still request conversions.

UUID needs a separate Vortex payload because canonical `arrow.uuid`
metadata must be empty. Keeping that representation lets other Arrow
tools recognize UUID columns. A field without the Vortex payload imports
with an unspecified version, so ordinary Arrow producers remain
supported.

Nested conversions need the full Arrow field because a `DataType` alone
cannot carry extension identity. GeoArrow's required child names also
belong to its layout contract. Metadata restoration uses inferred Vortex
storage because it can differ from Arrow's physical storage.

Regression coverage retains complete dtype and array comparisons while
removing redundant parameter products and assertions. Variant remains
excluded pending #11359, and equality derivation remains separate in
#11115.

## API Changes

Extension plugins implement `ArrowExtVTable`, declare
`metadata_policy()`, and register through
`ArrowSession::register_extension(vtable)`. The typed import callbacks
are associated functions. Raw plugins remain available, but inferred
fields and imported arrays must satisfy the same dtype checks.

<details>
<summary>Validation</summary>

- Formatting with the pinned `nightly-2026-09-10`.
- Commit hook: workspace Rust and TOML formatting.
- Pre-push hook: DCO checks and workspace Clippy with all targets, all
features, and warnings denied.
- Runtime tests, doctests, and fuzz runs were not repeated for these
refinements.

</details>

Signed-off-by: Connor Tsui <[email protected]>

## Summary

Follow-up to #11375 and [the DuckDB exporter
review](#11360 (comment)).

Chunked run-end inputs currently lose their cached dictionary when an
output batch crosses a chunk boundary. Exposing the existing batch codes
through `DictionaryParts` lets those ranges reuse the values dictionary,
including ranges shared with ordinary dictionary chunks.

## Changes

Keep the run-end specialization because routing through `to_dict()`
would make the generic exporter materialize the entire codes array. The
existing fill loop also remains: using `slice_relative_ends` increased
standalone single-row-run export time in all five trial pairs (median
paired ratio 1.064).

Empty inputs now avoid run lookup and values conversion, and zero-length
requests avoid scalar access. Constant batches include requests ending
exactly at a run boundary. Compact inline regressions cover empty
requests, slice offsets, exact run boundaries, nulls, successive
batches, and shared or different dictionaries across chunks. The
existing null and chunked-values tests remain.

Measurements on `702fd58dea`, before the test and module cleanup, showed
about 15% lower batch-export time for single-row runs and 16% for long
runs. Rust allocations per export loop fall from 146 to 112 and from 212
to 188, respectively. Standalone export and construction timings show no
clear material change. Native DuckDB allocations were not measured.

<details>
<summary>Validation</summary>

- After cleanup, `cargo nextest run -p vortex-duckdb -E
'test(exporter::run_end::)'`: 7 passed, 265 outside the filter.
- Before cleanup, the full exporter filter passed all 80 tests.
- `cargo clippy -p vortex-duckdb --all-targets --all-features -- -D
warnings`: passed.
- `cargo +nightly-2026-09-10 fmt -p vortex-duckdb`: passed.
- Commit hook: workspace Rust and TOML formatting passed.
- Pre-push hook: DCO checks and workspace Clippy with all targets, all
features, and warnings denied passed.
- Broader runtime suites and doctests were not run.

</details>

<details>
<summary>Benchmark methodology and full results</summary>

Baseline: `b367941e9d490b4a19ef9bdd6653f63d712c581f` with the same
benchmark harness. Candidate:
`702fd58dea3c0eeb214d590b3cc6d6b5b3c89c9b`. This comparison isolates the
follow-up from the Arrow extension/property stack.

The [measurement
harness](https://github.com/vortex-data/vortex/blob/702fd58dea3c0eeb214d590b3cc6d6b5b3c89c9b/vortex-duckdb/benches/run_end_export.rs)
and its Cargo target remain available in that measured commit. The
permanent benchmark target was removed during review, along with
duplicate test setup and the module split. The production algorithm is
unchanged, but these measurements were not rerun after the file move.

macOS 27.0.1, aarch64, rustc 1.99.1, LLVM 23.1.1, Cargo bench profile,
and DuckDB 2.0.0. Build both revisions with `cargo bench -p
vortex-duckdb --bench run_end_export --no-run`. Run their saved
executables with `--bench --sample-count 300 --sample-size 20 --color
never` in five pairs, alternating baseline/candidate order. The table
shows the median of each executable's five run medians, plus the median
of the five paired candidate/baseline ratios. These two aggregations
need not agree exactly.

Inputs are non-null i64 run values with run lengths 1 or 8192. Short-run
sources have 16,383 runs, and long-run sources have eight. Chunked
inputs repeat the same source four times. Every input is sliced from row
17 to 13 rows before its end, so exports span multiple batches and chunk
boundaries fall inside output batches. Fixtures execute the slice to its
encoded representation before exporter construction. Construction uses a
fresh conversion cache per iteration. Batch export uses a warm cache and
excludes exporter construction and data-chunk creation.

`AllocProfiler<MiMalloc>` counts Rust allocations in the measured
region, including its timing overhead. It does not count native DuckDB
allocations. Neither `xctrace` nor `heaptrack` is available on this
machine. Allocation figures below are allocation counts and requested
bytes, not peak resident memory.

| Phase | Input | Run length | Baseline (us) | Candidate (us) | Paired
ratio | All five paired ratios |
| --- | --- | ---: | ---: | ---: | ---: | --- |
| batches | standalone | 1 | 14.02 | 13.51 | 0.961 | 0.961, 0.954,
0.968, 0.949, 1.028 |
| batches | standalone | 8192 | 3.349 | 3.293 | 0.980 | 0.866, 1.007,
1.015, 0.926, 0.980 |
| batches | shared chunks | 1 | 48.3 | 41.15 | 0.851 | 0.849, 0.851,
0.858, 0.852, 0.850 |
| batches | shared chunks | 8192 | 19.74 | 16.57 | 0.839 | 0.839, 0.839,
0.833, 0.864, 0.832 |
| construct | standalone | 1 | 0.8631 | 0.8464 | 0.981 | 0.951, 0.979,
0.984, 0.981, 1.016 |
| construct | standalone | 8192 | 0.7922 | 0.7714 | 0.981 | 0.934,
0.982, 0.981, 0.966, 1.004 |
| construct | shared chunks | 1 | 51.69 | 51.68 | 1.000 | 1.012, 0.999,
0.997, 1.000, 1.000 |
| construct | shared chunks | 8192 | 12.9 | 12.88 | 0.998 | 1.002,
0.997, 0.998, 0.998, 0.998 |

| Phase | Input | Run length | Baseline Rust allocations | Candidate
Rust allocations | Baseline bytes | Candidate bytes |
| --- | --- | ---: | ---: | ---: | ---: | ---: |
| Batches | Standalone | 1 | 0 | 0 | 0 | 0 |
| Batches | Standalone | 8192 | 0 | 0 | 0 | 0 |
| Batches | Shared chunks | 1 | 146 | 112 | 193.1 KB | 130.5 KB |
| Batches | Shared chunks | 8192 | 212 | 188 | 200.2 KB | 139.3 KB |
| Construct | Standalone | 1 | 5 | 5 | 308 B | 308 B |
| Construct | Standalone | 8192 | 5 | 5 | 308 B | 308 B |
| Construct | Shared chunks | 1 | 32 | 32 | 265.8 KB | 265.8 KB |
| Construct | Shared chunks | 8192 | 22 | 22 | 1.05 MB | 1.05 MB |

The shared-chunk batch timing improved in every pair. Standalone
controls and construction moved much less, and the standalone long-run
ratios varied in direction. No compiler-output analysis was performed,
so those small movements are not attributed to a particular
code-generation change. These microbenchmarks do not establish an
end-to-end query speedup.

</details>

---------

Signed-off-by: Connor Tsui <[email protected]>

## Summary

QC `develop` is missing 13 upstream commits. Merge
`vortex-data/vortex:develop` at
`cb613ac1c0adc56cbe63dfc79e4bbc431ad0bc52` into QC `develop` at
`b2c429ac2830b883cb37c1ff9262dc9e3cb7e483`.

Merge this PR with a merge commit to preserve upstream ancestry for
future syncs.

## Changes

- Import typed Arrow extension plugins and round-trip metadata
preservation, run-end export fixes, and DuckDB dictionary reuse across
chunks ([vortex-data#11360](vortex-data#11360),
[vortex-data#11375](vortex-data#11375),
[vortex-data#11378](vortex-data#11378)).
- Bring in improved string dictionary selection, spatial contains/within
pruning, and safe PCO decoding
([vortex-data#9762](vortex-data#9762),
[vortex-data#11372](vortex-data#11372),
[vortex-data#11363](vortex-data#11363)).
- Include CUDA Widen execution, bounded dictionary gathers,
encoded-child host copies, and string dictionaries in the CUDA
compression preset.
- Reconcile the upstream Java I/O ports with their existing QC
implementations, preserving read metrics, Kryo-safe Hadoop broadcasts,
lifecycle handling, session defaults, and regression coverage. Correct
the coalescing default's Javadoc to 1 MiB.

## Testing

- Pinned `nightly-2026-09-10` Rust formatting for all affected crates,
root/subproject `./gradlew spotlessApply`, and clang-format for the
changed CUDA kernels passed. Reviewed and included the formatter diff.
- `git diff --check` passed; no unresolved merge entries or conflict
markers remain. The worktree is clean and both remote tips are parents
of the signed-off merge commit.
- All 13 imported commits have sign-off trailers and retain their
original upstream metadata.
- Tests, builds, lint, and benchmarks were not run locally, following
repository guidance.

---------

Signed-off-by: Daniel King <[email protected]>
Signed-off-by: Tanish Gudise <[email protected]>
Signed-off-by: Alexander Droste <[email protected]>
Signed-off-by: Christopher Wirt <[email protected]>
Signed-off-by: Nemo Yu <[email protected]>
Signed-off-by: Connor Tsui <[email protected]>
Signed-off-by: Will Manning <[email protected]>
Signed-off-by: Robert Kruszewski <[email protected]>
Co-authored-by: Dan King <[email protected]>
Co-authored-by: Tanish Gudise <[email protected]>
Co-authored-by: Claude Opus 5.5 <[email protected]>
Co-authored-by: Alexander Droste <[email protected]>
Co-authored-by: Connor Tsui <[email protected]>
Co-authored-by: Nemo Yu <[email protected]>
Co-authored-by: Will Manning <[email protected]>