refactor: reduce runtime dependencies

[KKould]

Summary

• remove direct dependencies on byteorder, fixedbitset, recursive, siphasher, ahash, and itertools
• replace them with std helpers, internal RowBitmap, StableHasher, std collections, and small local iterator helpers
• keep DataValue hash tagging and histogram null-count estimate fixes, and update affected tests/SLT expectations

Tests

• make test-all
• size comparison builds against main (561007d) and this PR (61b9e79)

Build Size Comparison

Measured with cargo build --release --no-default-features --features ... --example hello_world -p kite_sql and verified each binary runs to row count = 2.

Case	Features	main	This PR	Diff	Change
memory	orm	2,916,320 B / 2.78 MiB	2,819,264 B / 2.69 MiB	-94.8 KiB	-3.33%
lmdb only	orm,lmdb	3,557,088 B / 3.39 MiB	3,344,952 B / 3.19 MiB	-207.2 KiB	-5.96%
rocksdb only	orm,rocksdb	13,364,128 B / 12.75 MiB	13,179,080 B / 12.57 MiB	-180.7 KiB	-1.38%