After the AI titles a chat, ask the configured model to draw an SVG
icon for the title, rasterize it (sandboxed-worker validity gate plus
in-process vector draw with the fixedSVGData defs/use repair), and
show it circle-clipped next to the chat name. Chats without an icon
show a default chat-bubble icon. Forked chats inherit the source
chat's icon.

The prompt is editable in Settings > General > AI > Prompts (Chat
List Icon) and interpolates the title as \(ai.subject); the Settings
warning and help text cover the new prompt. Prompt-template
evaluation is unified in AIPromptTemplateEvaluator (one-shot
iTermExpressionEvaluator, shared by Engage AI, orchestration, and the
icon prompt). One-shot AIConversation retention is unified in
completeOneShot, replacing the per-site stored-property and static
dictionary patterns, and the rename flow no longer leaks its
conversation on asynchronous failure.

The icon is stored as a 128px PNG blob in the Chat table (with
migration), invalidated on title change, cached by the cell view, and
icon-only updates reload a single list row.