/iblai-prompts-tab

Add the agent Prompts tab -- displays four system prompts (system, proactive, study, guided) with edit/copy buttons and toggle switches, plus a suggested prompts section with add and edit modals. This is one tab in the wider agent-settings family. All tabs share the same AgentSettingsProvider wrapper.

Do NOT add custom styles, colors, or CSS overrides to ibl.ai SDK components. They ship with their own styling. Keep the components as-is. Do NOT implement dark mode unless the user explicitly asks for it.