feat: display toggles, smart session resume, fix stale transcript pane (#8)

src/lib/markdown.ts

@@ -28,6 +28,14 @@ export const STREAMING_CURSOR = "▍";
 export const USER_LABEL = "You";
 export const ASSISTANT_LABEL = "Lam";
 
+/** Which optional sections the transcript includes. Driven by preferences. */
+export interface TranscriptOptions {
+  showToolCalls: boolean;
+  showReasoning: boolean;
+}
+
+const SHOW_EVERYTHING: TranscriptOptions = { showToolCalls: true, showReasoning: true };
+
 /** Prefixes every line so a multi-line message stays one continuous quote block. */
 export function quote(text: string): string {
   return text
@@ -36,7 +44,7 @@ export function quote(text: string): string {
     .join("\n");
 }
 
-function renderMessage(message: ThreadMessage): string {
+function renderMessage(message: ThreadMessage, options: TranscriptOptions): string {
   if (message.role === "user") {
     return `**${USER_LABEL}**\n\n${quote(message.text)}`;
   }
@@ -51,14 +59,14 @@ function renderMessage(message: ThreadMessage): string {
     sections.push("", `**Error** — ${message.error}`);
   }
 
-  if (message.toolCalls.length > 0) {
+  if (options.showToolCalls && message.toolCalls.length > 0) {
     const lines = message.toolCalls.map(
       (call) => `- \`${call.name}\`${call.isError ? " — failed" : ""}`,
     );
     sections.push("", "**Tools used**", ...lines);
   }
 
-  if (message.thinking.trim().length > 0) {
+  if (options.showReasoning && message.thinking.trim().length > 0) {
     sections.push("", "_Reasoning_", "", quote(message.thinking.trim()));
   }
 
@@ -79,7 +87,10 @@ function renderMessage(message: ThreadMessage): string {
  * separates one exchange from the next rather than dividing every single
  * message.
  */
-export function buildThreadMarkdown(messages: ThreadMessage[]): string {
+export function buildThreadMarkdown(
+  messages: ThreadMessage[],
+  options: TranscriptOptions = SHOW_EVERYTHING,
+): string {
   if (messages.length === 0) return "";
 
   const blocks: string[] = [];
@@ -98,7 +109,7 @@ export function buildThreadMarkdown(messages: ThreadMessage[]): string {
       flush();
       currentTurn = turnId;
     }
-    buffer.push(renderMessage(message));
+    buffer.push(renderMessage(message, options));
   }
 
   flush();