feat(view): DVIEW twists the view about its line of sight

DVIEW (alias DV) offers TWist and Undo. TWist rolls the active view
or viewport camera to the typed angle; Undo steps back through the
twists made in the session. The new alias reaches existing profiles
through the alias migration table.

Refs #638

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

src/command.rs

@@ -1935,6 +1935,9 @@ pub enum CmdResult {
     PasteClipboard {
         base_pt: DVec3,
     },
+    /// Set the view's twist about its line of sight (radians,
+    /// counter-clockwise); the command stays active.
+    TwistView(f64),
     /// Zoom the model-space camera to fit the given corner points; end command.
     ZoomToWindow {
         p1: DVec3,