Let herdr's tab bar show the terminal background, so it turns glassy too (#15022)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

migrations/1791722809.sh

@@ -0,0 +1,21 @@
+echo "Let herdr's tab bar show the terminal's background, so it turns glassy too"
+
+config="$HOME/.config/herdr/config.toml"
+
+# Dotfile managers may own the file or a parent directory through a symlink.
+# Preserve that layout rather than detaching or editing its target.
+path="$config"
+while [[ $path != "$HOME" && $path != / ]]; do
+  if [[ -L $path ]]; then
+    echo "Preserving symlink-managed herdr config: $config"
+    exit 0
+  fi
+  path=$(dirname "$path")
+done
+
+# Only a tab bar still on the shipped black changes; any other choice is kept,
+# and a surface_dim of the user's own is never given a second one.
+if [[ -f $config ]] && grep -qx 'panel_bg = "black"' "$config" && ! grep -q '^[[:space:]]*surface_dim[[:space:]]*=' "$config"; then
+  sed -i 's/^panel_bg = "black"$/panel_bg = "reset"\nsurface_dim = "black"/' "$config"
+  omarchy-restart-herdr || true
+fi