[dfa1]

Four commits, one bug each (rebase-merge, don't squash):

1. ArrayStats mirrors Rust's array stats table. fromFbs dropped is_sorted, is_strict_sorted, is_constant, uncompressed_size_in_bytes and nan_count, and the record had a trueCount with no wire field (Rust has no TrueCount stat; a bool column's true count is its sum). Rust writes is_sorted/is_strict_sorted into flat array stats, so these now read back instead of null. Breaking: trueCount() and the 7-arg constructor are gone.
2. nan_count signedness. The count is u64, so pruning's > 0 read a value ≥ 2^63 as "no NaN". It now uses != 0, as Rust does. Only a corrupt file can trigger this, and there is no test for it.
3. Writer: mark flat min/max Exact. The precision was never written, so Rust read every Java-written bound as Inexact (the FlatBuffer default).
4. Reader: honor min/max precision. ArrayStats gains minExact/maxExact, read the way Rust's from_flatbuffer reads them: absent means Inexact, and any value other than 0/1 throws VortexException. Zone tables: vortex.zoned MIN/MAX are exact, a legacy *_is_truncated flag makes them inexact, and bounded_* values are never exact. columnStats() reports only exact min/max, and Calcite answers MIN/MAX only from exact stats. Range pruning still uses inexact bounds, which is safe; only the min == max == v cases require both bounds exact.

vortex-jni writes no flat min/max on its default path (checked by writing a file and reading its stats back), so no Rust-written file produces an inexact flat bound to cross-check against.

Tests:

• Unit tests for every stat field (false/0 values, which equal the FlatBuffer defaults) and for exact, absent and corrupt precision.
• vortex-jni cross-check VortexInspectorIntegrationTest#peek_readsSortednessRustRecordsInFlatArrayStats: Rust's sorted flags read back. It fails if is_sorted is dropped.
• vortex-jni cross-check JavaWritesRustReadsIntegrationTest#javaWriter_jniReader_filteredUtf8_prunesOnTruncatedBounds: vortex-jni filters a Java-written column of keys longer than 64 bytes, and Java's columnStats() returns the full keys. It fails without the writer fix.

Full ./mvnw verify passes locally (9198 tests).

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