fix: crop save dropped blue channel brightness/contrast offset (v1.4.2)

m[13] (blue alpha coefficient, always 0) was read as the blue offset instead of
m[14], so saved JPEGs lost the blue brightness/contrast offset and came out with a
color cast. Saturation/rotate were unaffected (no offsets).

Also: version 1.4.2, CHANGELOG entry, dist/ ships imajviewer_1.4.2_amd64.deb
(replaces 1.4.1).

CHANGELOG.md

@@ -4,6 +4,13 @@ All notable changes to imajViewer are documented in this file.
 
 ## [Unreleased]
 
+## [1.4.2] - 2026-10-12
+
+### Fixed
+- Crop save dropped the blue channel's brightness/contrast offset (matrix index `m[13]`, the
+  alpha coefficient, instead of `m[14]`), so saved JPEGs came out with a color cast whenever
+  brightness or contrast was applied. Saturation/rotate were unaffected.
+
 ## [1.4.1] - 2026-10-11
 
 ### Fixed