fix: tray restart uses python -m for reliable process respawn

The previous os.execv approach and console_script detection both
failed on Windows. Now restart always spawns `python -m media_server.main`
via subprocess.Popen with start_new_session, which works regardless
of how the server was originally started.

media_server/main.py

@@ -277,6 +277,20 @@ def main():
 
         # Tray exited — wait for server to finish graceful shutdown
         server_thread.join(timeout=10)
+
+        if tray.restart_requested:
+            import subprocess
+
+            # Always restart via `python -m media_server.main` — this works
+            # regardless of how we were originally started (console_script,
+            # python -m, or direct script invocation).
+            cmd = [sys.executable, "-m", "media_server.main"]
+
+            subprocess.Popen(
+                cmd,
+                cwd=Path.cwd(),
+                start_new_session=True,
+            )
     else:
         uvicorn.run(
             "media_server.main:app",