v1.8.91: terminal background pure black (#000000) instead of dark blue

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

gui/widgets/terminal_widget.py

@@ -35,8 +35,8 @@ _ANSI_COLORS = {
 }
 
 _DEFAULT_FG = "#d3d7cf"
-_DEFAULT_BG = "#1a1a2e"
-_CURSOR_FG  = "#1a1a2e"
+_DEFAULT_BG = "#000000"
+_CURSOR_FG  = "#000000"
 _CURSOR_BG  = "#d3d7cf"
 
 # ── Private mode constants (pyte stores private modes shifted <<5) ─────────