Bump to v2.0.0: ASIO startup splash so launch no longer looks frozen

Opening an ASIO driver takes 1-3 seconds, synchronously, during MainForm
construction — confirmed in logs as a ~2.8s dead gap on an ASIO-profile
launch (a WASAPI-only launch is ~131ms for the same stretch). During that
gap the main window is blank / "Not Responding" and looks hung.

New AsioLoadingSplash shows a small "Loading audio driver, please wait..."
window on its OWN dedicated STA thread with its own message loop, so it
stays painted while the main thread is blocked opening the driver.
Program.cs starts it before new MainForm() and dismisses it after.

Deliberately, the ASIO driver open stays on the main UI thread — that
STA/message-pump thread is what ASIO/COM drivers are most compatible with,
and moving the open off it risks breaking drivers that can't be tested.
Only the cosmetic splash moved to a side thread; no ASIO/driver code is
touched. Splash shows only for profiles with an ASIO driver selected;
WASAPI-only profiles build fast and get no splash.

Version bumped to 2.0.0 to mark the milestone.

No wire-format or audio-pipeline changes — v1.5 through v2.0 interoperate.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/RemSound.App/AboutDialog.cs

@@ -20,6 +20,22 @@ internal sealed class AboutDialog : Form
     /// updates" path.</summary>
     private const string ReleaseNotes =
         """
+        RemSound v2.0
+
+        A smoother startup when a profile uses an ASIO driver.
+        No wire-format or audio-pipeline changes — v1.5 through
+        v2.0 peers interoperate.
+
+        Change:
+          * Opening an ASIO driver takes a couple of seconds,
+            and during that time the main window used to look
+            frozen on startup. RemSound now shows a small
+            "Loading audio driver" window while the driver
+            opens, so startup no longer looks hung. The window
+            then opens as normal. Profiles that don't use an
+            ASIO driver are unaffected — they still start
+            instantly, with no extra window.
+
         RemSound v1.9
 
         Critical auto-updater fix. No wire-format or