feat: render LaTeX, custom HTML and diagrams in the transcript (#19)

src/lib/markdown.ts

@@ -1,5 +1,5 @@
 import { imageSource } from "./attachments";
-import { repairCodeBlocks } from "./code";
+import { renderInlineContent, renderModelOutput } from "./render";
 import { describeActivity } from "./thread";
 import type { Attachment, ChatTurn, ThreadMessage, ToolCallRecord } from "./types";
 
@@ -117,10 +117,13 @@ function renderToolFailureNote(message: ThreadMessage): string | undefined {
 }
 
 function renderMessage(message: ThreadMessage, options: TranscriptOptions): string {
-  // The question is identified by its styling alone.
+  // The question is identified by its styling alone. It goes through the same
+  // rendering pass as an answer, because a person pastes LaTeX into a question
+  // as readily as a model writes it, and a question full of raw HTML should be
+  // put behind the same fence.
   if (message.role === "user") {
     const images = renderAttachments(message.attachments);
-    const asked = quote(message.text);
+    const asked = quote(renderInlineContent(message.text));
 
     return images ? `${asked}\n\n${images}` : asked;
   }
@@ -148,10 +151,10 @@ function renderMessage(message: ThreadMessage, options: TranscriptOptions): stri
   /** The answer, or whatever stands in for it while there is none. */
   const answered = message.text.trim();
   const body = answered
-    ? // Fences without a language render as a plain dark panel, and a lone
-      // inline command renders as a chip with no Copy button at all. Both are
-      // repaired before the markdown reaches the renderer.
-      repairCodeBlocks(answered)
+    ? // One pass, in one place: fences get their languages and links recovered,
+      // then TeX becomes something drawable and the HTML around it is filtered to
+      // the subset the renderer acts on. See `render.ts` for the order and why.
+      renderModelOutput(answered)
     : !message.isStreaming
       ? "_No response._"
       : activityLine