Add wIRC main scrollback, route services to it, remember window bounds, bump to 0.1.7

wIRC main scrollback
- The main window now has a "Server messages" scrollback using the same
  rendering and stick-to-bottom code as channel windows (extracted from
  ChannelScreen into a shared MessageScrollback composable).
- MOTD, numerics, errors, connection status, user modes, INVITE, ERROR,
  non-ACTION CTCP requests and notices/messages from services
  (NickServ, ChanServ, *Serv, Global, ...) and the server go there. Its
  history persists like any other buffer (history/wirc-main__main.json).
- Unread indicator: lines arriving while the main window is unfocused
  show as "N new" next to the label and in the window title/taskbar.

Private messages and /whois
- A PM or notice from a real user opens its query window, and reopens it
  if it was closed. Services and the server no longer open windows.
- /whois <nick> sends WHOIS and shows the formatted reply in the window
  it was typed in, or in wIRC main if that window has since closed.
- /me now sends a proper CTCP ACTION (the \x01 wrapper was missing).

Window position and size
- Main, channel and PM windows remember position and size in
  window_prefs.json under the existing "<serverId>__<name>" key (main
  uses "wirc-main__main"). The new windowX/windowY/windowWidth/
  windowHeight fields are optional, so older files still load.
- A saved position is only used if the window's title strip is on a
  connected monitor; otherwise, and for windows with no saved position,
  windows cascade from the primary screen's top-left with a 32dp offset.
- window_prefs.json is now written via a temp file + atomic move.

Cleanup
- Remove the TEMP DEBUG aliasDebug tracing, ServerRepository.upsert
  printlns and connmgr-debug printlns.

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

build.gradle.kts

@@ -6,7 +6,7 @@ plugins {
 }
 
 group = "com.tpuahsiew.wirc"
-version = "0.1.6"
+version = "0.1.7"
 
 // 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 = "0.1.6"
+            packageVersion = "0.1.7"
             windows {
                 menuGroup = "wIRC"
                 upgradeUuid = "8f14e45f-ceea-4a5e-9c3b-5b1f0e8c2b7a"