Motivation

• Improve the UX of the dashboard slot swap flow by clearly indicating which slot is the current swap source.
• Preserve existing swap semantics where the first chosen slot becomes the source and the second choice triggers the swap of slot data.
• Make it easy to cancel a pending swap by toggling the source again.

Description

• Updated src/gui/dashboard_editor_dialog.rs to render the per-slot swap button with a distinct filled color when self.swap_anchor == Some(idx) so the source is visually highlighted.
• Changed the displayed label from "Swap" to "Swap source" for the active source and used ui.add(...) with egui::Button::fill(egui::Color32::from_rgb(60,120,200)) to provide color feedback.
• Kept existing swap behavior that calls swap_slots(...) to exchange widget, settings, and id between slots and resets self.swap_anchor after a swap or cancel.
• No changes were made to the swap_slots validation or swapping logic itself.

Testing

• No automated tests were run for this change.

Codex Task