feat(coding-agent/modes): added debug transcript export command to dump visible TUI conversation

- Added transcript export option to debug menu that writes visible TUI conversation to a temporary text file.
- Implemented handleDebugTranscriptCommand in CommandController to render chat messages, strip ANSI codes, and write to temp directory.
- Updated InteractiveModeContext interface and InteractiveMode to expose the new debug transcript command handler.

packages/coding-agent/src/modes/controllers/command-controller.ts

@@ -28,6 +28,7 @@ import type { AuthStorage } from "../../session/auth-storage";
 import { createCompactionSummaryMessage } from "../../session/messages";
 import { outputMeta } from "../../tools/output-meta";
 import { resolveToCwd } from "../../tools/path-utils";
+import { replaceTabs } from "../../tools/render-utils";
 import { getChangelogPath, parseChangelog } from "../../utils/changelog";
 import { openPath } from "../../utils/open";
 
@@ -70,6 +71,25 @@ export class CommandController {
 		}
 	}
 
+	async handleDebugTranscriptCommand(): Promise<void> {
+		try {
+			const width = Math.max(1, this.ctx.ui.terminal.columns);
+			const renderedLines = this.ctx.chatContainer.render(width).map(line => replaceTabs(Bun.stripANSI(line)));
+			const rendered = renderedLines.join("\n").trimEnd();
+			if (!rendered) {
+				this.ctx.showError("No messages to dump yet.");
+				return;
+			}
+			const tmpPath = path.join(os.tmpdir(), `${Snowflake.next()}-tmp.txt`);
+			await Bun.write(tmpPath, `${rendered}\n`);
+			this.ctx.showStatus(`Debug transcript written to:\n${tmpPath}`);
+		} catch (error: unknown) {
+			this.ctx.showError(
+				`Failed to write debug transcript: ${error instanceof Error ? error.message : "Unknown error"}`,
+			);
+		}
+	}
+
 	async handleShareCommand(): Promise<void> {
 		const tmpFile = path.join(os.tmpdir(), `${Snowflake.next()}.html`);
 		const cleanupTempFile = async () => {