feat(app): render image content parts in the message viewer

[cacoos]

Problem

The Workshop message viewer is text-only. messageParsing.ts extracts just type:"text" blocks and discards every other content part, so image parts never render — even though they're present in the raw payload (visible via the Raw toggle).

This bites any agent that feeds the model a screenshot. Concretely, a readPage-style tool appends a user message like:

{ "role": "user", "content": [
  { "type": "text", "text": "This is a screenshot of the page at https://..." },
  { "type": "image", "image": "https://...cloudfront.../read-page-....jpg" }
]}

Workshop shows the text bubble but draws nothing for the image, so it looks like the screenshot was lost when it wasn't:

Fix

Parse image/file content parts into a new optional Message.images and render them as thumbnails (click to open full size).

• messageParsing.ts — extractImageSrc pulls a displayable <img> src out of the common shapes:

  • AI SDK { type: "image", image: <url | data-uri | base64> }
  • AI SDK / provider-normalized { type: "file", mediaType: "image/*", data: <url> } (the shape the AI SDK normalizes image parts to)
  • Anthropic { type: "image", source: { type: "base64" | "url", ... } }
  • bare base64 is wrapped into a data: URI using the block's media type

  Images are collected in both the raw-payload path (parseMessages) and the normalized-span path (messagesFromSpan). Image-only messages (no text) are now kept instead of filtered out.

• MessageList.tsx — new reusable MessageImages component; MessageBubble renders images under the text and shows an "N images" preview when a message has no text.

• ChatFlow.tsx — threads images through the user_msg item so appended screenshot messages render in the conversation flow (the surface where this was reported).

Non-image blocks (tool_use, tool_result, text) are unchanged. The new field is optional, so all existing Message consumers are unaffected.

Verification

tsc --noEmit is clean for the changed files. Parser verified against the four payload shapes above (AI SDK image, file/image/*, Anthropic base64 source, and the normalized-span path) — each yields the expected images array while text and non-image parts are preserved, and an image-only message is retained with content: "".

Notes

• Thumbnails are capped at max-h-64 and wrapped in a link to the full-size source.
• Data URIs and http(s) URLs are used directly; only bare base64 is wrapped with a media type.