feat(console): toolbar toggle to hide per-line color accent bars

Adds a paint-bucket toggle button to the console toolbar (in the appearance
cluster next to zoom) that shows/hides the per-line left color accent bars for
a cleaner monochrome gutter. The icon reflects state (FORMAT_COLOR_FILL when on,
a dimmed FORMAT_COLOR_RESET when off) with a tooltip. Session-only, like the
console zoom factor; default on.

Adds console_toggle_accents to the English source and all eight translations
(no new CJK glyphs — the subset font already covers them).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/windows/console_tab.h

@@ -69,6 +69,9 @@ public:
     // Console output zoom factor (1.0 = default caption font size)
     static float s_console_zoom;
 
+    // Draw the per-line left color accent bars (channel-colored). Toggled from the toolbar.
+    static bool s_line_accents_enabled;
+
     // Show/hide daemon output messages
     static bool s_daemon_messages_enabled;