feat(popup): opaque CherryBlossom popup style and rounded border

tmux.conf

@@ -180,6 +180,12 @@ set -g pane-active-border-style "fg=#{@tab-active-fg}"
 set -g message-style "bg=default,fg=#{@tab-active-fg}"
 set -g message-command-style "bg=default,fg=#{@tab-active-fg}"
 set -g mode-style "bg=#{@tab-active-bg},fg=#{@tab-active-fg}"
+# Popups (lazygit, tasks, keybindings): explicit bg so Ghostty draws them
+# opaque (background-opacity only applies to default-bg cells; a default-bg
+# popup shows the pane behind it through the blur).
+set -g popup-style "bg=#{@tab-bg},fg=#dcc1b7"
+set -g popup-border-style "bg=#{@tab-bg},fg=#{@tab-active-fg}"
+set -g popup-border-lines rounded
 setw -g clock-mode-colour blue
 
 # Plugins (tpm, cloned by .chezmoiexternal.toml). prefix + I installs,