feat(writer): global-dict Binary columns like Rust's dict layout

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Read and write `vortex.onpair` (unstable edition `unstable2026.06.0`): `tpch_orders.regular` and `clickbench_hits_5k.regular` from the v0.86.1 fixtures now scan, and `WriteOptions.withEdition(Editions.UNSTABLE_2026_06_0)` lets the cascade pick OnPair for string columns ([#425](https://github.com/dfa1/vortex-java/issues/425)).
 
 ### Changed
+- Low-cardinality `Binary` columns are now written as a global dictionary, as Rust does for `Primitive`, `Utf8` and `Binary`; before, only primitive and `Utf8` columns were ([#443](https://github.com/dfa1/vortex-java/pull/443)).
 - With an unstable edition enabled (`WriteOptions.withEdition(Editions.UNSTABLE_2025_05_0)` or later), cascading writes can pick `fastlanes.delta`, its bases and deltas cascaded as in Rust; default writes never emit it ([#439](https://github.com/dfa1/vortex-java/pull/439)).
 - The writer run-length encodes float columns too (`fastlanes.rle`, as Rust's float RLE scheme does), losslessly: `-0.0` and NaN payloads round-trip ([#438](https://github.com/dfa1/vortex-java/pull/438)).
 - Cascading writes (`WriteOptions.cascading(n)`) compress run-end columns further: the run ends and values now go through the cascade (bit-packing, frame-of-reference, …) instead of being stored raw, as in Rust; about 1% smaller on the mixed-column size benchmark ([#435](https://github.com/dfa1/vortex-java/pull/435)).

docs/compatibility.md

@@ -40,7 +40,7 @@ only the built-in decoders in `reader`; no encoder class is loaded.
 | `vortex.onpair` experimental string encoding | Rust 0.74.0 | ✅ Read and written. The writer emits it only when `WriteOptions.withEdition(Editions.UNSTABLE_2026_06_0)` is set; the trained dictionary is valid for Rust but not byte-identical to Rust's (Rust's sampling RNG is not portable). |
 | `vortex.variant` arbitrary nested objects | Rust (`vortex.parquet.variant`) | ⚠️ Java encodes/decodes variant columns of **typed scalar** values (constant / chunked-of-constants core, optional shredded child); Java↔Rust round-trip verified. Arbitrary nested JSON objects and real path-based shredding need the `vortex.parquet.variant` physical encoding — deferred ([ADR 0014](../adr/0014-variant-encoding-strategy.md)). |
 | Arrow extension array import affecting Variant shape | Rust 0.74.0 (#8125) | Untested against the currently pinned v0.85.0 fixtures; #8125 not yet re-verified. |
-| `vortex.dict` **layout** over a values pool that is neither VarBin- nor primitive-shaped (e.g. a dict-encoded `vortex.uuid`, whose storage is `FixedSizeList(U8, 16)`) | Rust's dict layout accepts any dtype | ❌ No lazy dict carrier exists for that pool shape, so decode throws `VortexException("unsupported dict values shape: …")`. The `vortex.dict` *encoding* is unaffected. |
+| `vortex.dict` **layout** over a values pool that is neither VarBin- nor primitive-shaped (e.g. a dict-encoded `vortex.uuid`, whose storage is `FixedSizeList(U8, 16)`) | Not written by Rust: its dict layout admits only `Primitive \| Utf8 \| Binary` (`dict_layout_supported`), and its dict compressor schemes only integers, floats and strings | ⚠️ Unreachable from Rust- or Java-written files. Every type vortex-jni writes reads back exactly, dict-encoded or not (`DictAllTypesInteropIntegrationTest`, which also fails if a Rust bump starts dict-encoding another type). A foreign file with such a pool fails with `VortexException("unsupported dict values shape: …")`. |
 | Duplicate struct field names | Rust writer rejects ("StructLayout must have unique field names"); Rust reader tolerates foreign files (first-match access) | ⚠️ Deliberate divergence on read: Java rejects such files with `VortexException("duplicate field name in file schema")` instead of tolerating them — the name-keyed `Chunk` API cannot represent both columns, and silent column loss is worse than a loud failure on a file the reference writer refuses to produce. Java's writer mirrors the Rust writer's rejection. |
 | Blank / control-character field names | Wire-legal; the Rust writer produces `""` and whitespace-only names. NUL (`U+0000`) additionally aborts the Rust toolchain: Arrow FFI schema export hits a panic-cannot-unwind in `arrow-rs` (`ffi_stream::get_schema`) and SIGABRTs the process (measured against vortex-jni 0.75.0) | ⚠️ Deliberate strictness BOTH ways: vortex-java's writer refuses blank and control-character field names (`IllegalArgumentException`), and its reader rejects files carrying them (`VortexException` naming the producing pipeline as the likely bug) — the JSON-`""`-key principle: wire-legal is a floor, not a policy. Printable names of any shape (`$`-runs, spaces inside, emoji) are legal and round-trip intact both directions (measured; pinned by `ColumnNameEdgeCasesIntegrationTest`). |