Interface PresentationPolicy

Where and how to surface an error in the UI.

placement:

• "silent" — swallow entirely; do not show anywhere.
• "panel" — log to the notifications panel only (background errors).
• "panel+toast" — log + ephemeral toast (global user-initiated ops).
• "panel+inline" — log + inline message inside the triggering surface.
• "inline" — inline only; panel is optional/omitted for low-signal cases.

severity maps directly to the UI severity indicator.