Fade title-bar buttons in on hover, remove temp debug logger, bump to 0.1.6

- Nicklist, settings, minimize and close buttons in the channel window
  title bar now rest at alpha 0 and fade to full opacity on hover
  (graphicsLayer alpha, so they stay laid out and clickable). Resting
  alpha, hover alpha and fade duration are constants at the top of
  ChannelScreen.kt. Channel name and window dragging are unchanged.
- Remove the unused temporary ircUiDebug helper now that the scrollback
  fix is confirmed.
- Bump version to 0.1.6.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

build.gradle.kts

@@ -6,7 +6,7 @@ plugins {
 }
 
 group = "com.tpuahsiew.wirc"
-version = "0.1.5"
+version = "0.1.6"
 
 // No project-level repositories{} block here: settings.gradle.kts sets
 // dependencyResolutionManagement.repositoriesMode = FAIL_ON_PROJECT_REPOS and already
@@ -38,7 +38,7 @@ compose.desktop {
             appResourcesRootDir.set(project.file("installerResources"))
             targetFormats(TargetFormat.Msi, TargetFormat.Exe)
             packageName = "wIRC"
-            packageVersion = "0.1.5"
+            packageVersion = "0.1.6"
             windows {
                 menuGroup = "wIRC"
                 upgradeUuid = "8f14e45f-ceea-4a5e-9c3b-5b1f0e8c2b7a"