Speak-status: drop the double-press-copy Preferences toggle

Andre confirmed (via NVDA speech history) that holding the speak-status hotkey
doesn't repeat or spam — so the defensive toggle that let users disable the
double-press-to-copy was needless configurability. Removed the Preferences
checkbox and the DoublePressStatusToCopy setting; double-press-to-copy (Andre's
own idea) stays, now simply always on. There was never any debounce/anti-spam
code to remove — the only timing is the 600 ms double-tap detection window, which
is the feature itself. Manual updated to drop the toggle line.

Held for the next release (the toggle never shipped).

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

src/RemSound.Core/AppConfig.cs

@@ -196,11 +196,6 @@ public sealed class AppConfig
     public bool? UntickOthersWhenUsingDefaultOutput { get; set; }
     public bool? UntickOthersWhenUsingDefaultInput { get; set; }
 
-    /// <summary>If true, pressing the "speak status" global hotkey twice in quick succession copies the
-    /// status text to the clipboard (instead of just reading it again). On by default; the user can turn
-    /// it off on the Preferences General tab. Machine-wide; a screen-reader convenience (Andre's idea).</summary>
-    public bool DoublePressStatusToCopy { get; set; } = true;
-
     /// <summary>If non-null and a profile with this title exists, RemSound skips the
     /// startup profile picker and loads this profile directly. Combine with
     /// <see cref="StartMinimised"/> + the Windows auto-start registry entry