v0.8.3

A Sonar-driven refactoring release: no new file-format capability, but a focused pass using SonarCloud findings to drive cleanups — dead code removed, duplication factored out, and one hot-loop micro-optimisation. Each finding was triaged (lead, not verdict) so the changes preserve behaviour and the JIT vectorisation of the hot decode loops. The interpretation framework behind this is now documented in docs/testing.md.

Performance

• FastLanes.transposeIndex / iterateIndex: replaced the per-element %// + ORDER[] indirection with permutation tables built once in a static initialiser. Faster address generation keeps more outstanding scatter misses in flight; measured 1.4×–3.4× on the transpose/undelta kernels (Apple M5, L1→DRAM working sets). The per-element decode loops stay specialised per width to preserve C2 superword vectorisation. (089b6e36, e683a634)

Removed

• Breaking (read SPI): removed EncodingDecoder.accepts(DType). It was a residual of the ADR-0001 read/write split — encode-selection semantics copied onto the decoder side, where the reader dispatches purely by EncodingId and never called it (dead since the split). EncodingEncoder.accepts is unchanged. Downstream custom EncodingDecoder implementations should delete their accepts override. (7516a544)

Changed

• Internal dedup driven by Sonar duplication findings: extracted the shared FastLanes layout + PType.bits and PrimitiveArrays.toLongs/fromLongs into core, hoisted the Materialized* array boilerplate into a shared base, factored the four BitpackedEncodingDecoder unpack loops onto one precomputed per-row schedule, added PType.isUnsigned (dropping three private copies), and deduplicated the CLI inspect plumbing and formatBytes. (ec6b9631, a74263c0, 7af0af2a, 8362a353, 87c77cc9, d8f84088, b557e573, d52e8c0c)
• Dropped dead PType switch arms in the writer's readPrimitiveElement, primitiveArrayLen, and buildTypedUniqueArray — unreachable branches flagged as uncovered. (4c6ab149, 94d2fa49, f89072a6)

Fixed

• Cleared two SonarCloud-reported bugs in the writer's SUM zone-map stat plumbing. (33798ab9)
• Suppressed java:S1172 on AbstractMaterializedArray.materialize with a reason — the arena parameter is contractual (implements Array#materialize(SegmentAllocator) for the leaf classes), not a removable unused parameter. (9b226f73)

Tests

• Filled coverage gaps surfaced by Sonar: the Materialized* materialize defaults, every SchemaCommand.formatDType arm, and the writer's global-dict cardinality fallback with U16 utf8 codes. (8741dad3, 77fad504, c2918eaa)

Docs

• docs/testing.md: new section on reading Sonar/PIT as data — the uncovered-line triage (missing-test / dead-code / defensive-by-contract), why mutation testing splits what coverage cannot, and when duplication is the deliberate price of the hot-loop rule. (8999661b)