Release v4.2: fix connect-freeze (#10) and new-profile minimize (#12); smoother WASAPI timing

- Connect no longer freezes: PushDiscoveryUnicastHints resolved remembered
  hostnames with synchronous Dns.GetHostAddresses on the UI thread, blocking the
  whole window for the DNS timeout on an unresolvable name. A screen-reader user
  experiences that as the entire machine locking up. Resolution now runs off the
  UI thread. Same class of bug as the v3.0.1 UPnP-on-the-UI-thread hang. (#10)

- New profile / profile switch no longer hides the window: OnShown ORed the
  global StartMinimised into every instance, so creating a new profile while
  Start minimised was on dropped the window to the tray and looked like a crash.
  StartMinimised now applies only to a genuine cold launch; relaunches honour the
  explicit per-instance flag. (#12)

- Smoother WASAPI audio: the receive producer loop and sender mix loop pace
  themselves with WaitHandle.WaitOne, bound by the system timer (~15.6ms default).
  Without a fine timer the 10ms feed slips to ~16-31ms and delivers audio in
  chunky bursts (the desktop-render chunkiness behind Andre's dropouts/lag). New
  SystemTimerResolution holds a 1ms timer whenever a stream is live, independent
  of the opt-in Priority mode.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/RemSound.App/AboutDialog.cs

@@ -20,6 +20,36 @@ internal sealed class AboutDialog : Form
     /// updates" path.</summary>
     private const string ReleaseNotes =
         """
+        RemSound v4.2
+
+        Three fixes, one of them a real annoyance gone.
+
+        Connecting to someone no longer risks a freeze.
+        If you had a peer saved by name and that name
+        couldn't be looked up quickly, RemSound used to
+        stall for a few seconds while it waited — and
+        because your screen reader waits on RemSound, the
+        whole computer could seem to lock up. That lookup
+        now happens out of the way, so connecting stays
+        responsive.
+
+        Creating a new profile (Ctrl+N), or switching
+        profiles, no longer drops the window to the tray
+        when you have "start minimised" turned on.
+        Starting minimised is meant for when RemSound
+        first launches, not for something you did on
+        purpose — so a new profile now comes up the normal
+        way (or stays in the tray only if that's where you
+        already were), instead of vanishing and looking
+        like a crash.
+
+        And WASAPI audio is smoother. RemSound now keeps
+        Windows' timing fine while it's streaming, so audio
+        moves in even steps instead of arriving in clumps.
+        On machines where playback was breaking up or
+        running laggy on WASAPI, this should help — and you
+        no longer need Priority mode switched on to get it.
+
         RemSound v4.1
 
         A couple of small fixes for screen-reader users. When