feat: add markdown image gallery previews

packages/ui/src/components/chat/message/parts/AssistantTextPart.tsx

@@ -19,6 +19,7 @@ interface AssistantTextPartProps {
     chatRenderMode?: 'sorted' | 'live';
     onContentChange?: (reason?: ContentChangeReason, messageId?: string) => void;
     onShowPopup?: (content: ToolPopupContent) => void;
+    enableMarkdownImages?: boolean;
 }
 
 const AssistantTextPart: React.FC<AssistantTextPartProps> = ({
@@ -27,6 +28,7 @@ const AssistantTextPart: React.FC<AssistantTextPartProps> = ({
     streamPhase,
     chatRenderMode = 'live',
     onShowPopup,
+    enableMarkdownImages = false,
 }) => {
     // Use part directly from props — parent provides the latest version from the store.
     // No store subscription here to avoid re-render cascade from unrelated delta events.
@@ -101,6 +103,7 @@ const AssistantTextPart: React.FC<AssistantTextPartProps> = ({
                 disableStreamAnimation={chatRenderMode === 'sorted'}
                 variant={part.type === 'reasoning' ? 'reasoning' : 'assistant'}
                 enableFileReferences={isFinalized}
+                enableLocalImages={enableMarkdownImages && !isStreaming && part.type === 'text'}
                 onShowPopup={onShowPopup}
             />
         </div>

packages/ui/src/components/chat/message/parts/DOCUMENTATION.md

@@ -55,6 +55,19 @@ Use this doc when you ask an agent to change tool/header/description behavior.
   HTML is sanitized as defense in depth, with script and style elements
   forbidden, so message content cannot inject active DOM or application-wide
   CSS into any runtime surface.
+- Final assistant Markdown collects HTTP(S), embedded, and workspace-local
+  PNG/JPEG/GIF/WebP image candidates into one 100px thumbnail gallery in the
+  message-completion area after all message text and above the turn's changed
+  files. Each muted filename caption includes the shared image-file icon.
+  HTTP(S) images keep their browser URL. Embedded and workspace-local images
+  are limited to 10 MiB, validated as PNG/JPEG/GIF/WebP, and local paths are
+  fetched through the active runtime before conversion to data URLs. Local
+  Markdown links whose target has one of
+  those image suffixes stay links in the text and open the same standard modal
+  preview as the gallery; image syntax does not insert a large inline image. A
+  completed assistant message hydrates at most 12 unique image candidates,
+  including persisted text parts that omit their optional part-level end time.
+  The image modal reserves readable title width even for narrow portrait media.
 - `read` and `skill` are **static navigation tools** and render via `StaticToolRow`.
 - Every other tool, including search/fetch, OpenCode built-ins, custom tools, plugins, and MCP tools, is **expandable** and renders through `ToolPart`.
 - The managed `openchamber` plugin tool uses the expandable path and hides its broad protocol input. The plugin supplies the selected action's human description as the native tool title; the UI renders that metadata without owning an action map. The full versioned result envelope renders through the same neutral JSON summary/tree/raw views as other tools, without a tool-specific output card.