[vortex] Do not push nanosecond timestamp literals that overflow int64

[jackylee-ch]

Purpose

For TIMESTAMP(7..9), toTimestampLiteral computes ts.getMillisecond() * 1_000_000 + ts.getNanoOfMillisecond(). A TIMESTAMP reaches year 9999, so a literal outside roughly [1677-09-21, 2262-04-11] overflows int64: 9999-12-31 00:00:00, a common open upper bound, becomes -4852202631933722624 ns — year 1816.

A wrapped bound turns >/>= into a superset the post-scan filter repairs, so only <, <= and = silently lose rows — hence unnoticed.

#9675 added the grain checks just above; this extends the same refuse-to-push contract to representability, returning null so the caller drops the leaf.

Tests

VortexPredicateConverterTest#testTimestampNanosOverflowingLiteralNotPushed. Reverting the fix:

expected: <null> but was: <dev.vortex.api.Expression@69c93ca4>

Written with Claude Code; verification is mine.