Bump version to 1.7.4

Changes in 1.7.4:
- Fix: base monomer period=0 for undecomposed HOR monomers caused
  mono_consensus/mono_period mismatch in summary.tsv (15% of arrays)
- New: period_classes column in summary.tsv showing size class distribution

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ad3002

src/rust/arraysplitter/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "arraysplitter_rs"
-version = "1.7.3"
+version = "1.7.4"
 edition = "2021"
 authors = ["Aleksey Komissarov <ad3002@gmail.com>"]
 description = "De novo decomposition of satellite DNA arrays into monomers"