feat(coding-agent): add extension project trust decisions

packages/tui/src/tui.ts

@@ -1282,15 +1282,17 @@ export class TUI extends Container {
 					fullRender(true);
 					return;
 				}
-				if (extraLines > 0) {
-					buffer += "\x1b[1B";
+				const clearStartOffset = newLines.length === 0 ? 0 : 1;
+				if (extraLines > 0 && clearStartOffset > 0) {
+					buffer += `\x1b[${clearStartOffset}B`;
 				}
 				for (let i = 0; i < extraLines; i++) {
 					buffer += "\r\x1b[2K";
 					if (i < extraLines - 1) buffer += "\x1b[1B";
 				}
-				if (extraLines > 0) {
-					buffer += `\x1b[${extraLines}A`;
+				const moveBack = Math.max(0, extraLines - 1 + clearStartOffset);
+				if (moveBack > 0) {
+					buffer += `\x1b[${moveBack}A`;
 				}
 				buffer += "\x1b[?2026l";
 				this.terminal.write(buffer);

packages/tui/test/tui-shrink.test.ts

@@ -0,0 +1,44 @@
+import assert from "node:assert";
+import { describe, it } from "node:test";
+import { type Component, TUI } from "../src/tui.ts";
+import { VirtualTerminal } from "./virtual-terminal.ts";
+
+class Lines implements Component {
+	private lines: string[];
+
+	constructor(lines: string[]) {
+		this.lines = lines;
+	}
+
+	render(): string[] {
+		return this.lines;
+	}
+
+	invalidate(): void {}
+}
+
+describe("TUI shrinking content", () => {
+	it("clears all rendered lines when content shrinks to zero", async () => {
+		const terminal = new VirtualTerminal(40, 10);
+		const tui = new TUI(terminal);
+		const content = new Lines(["first", "second", "third"]);
+		tui.addChild(content);
+		tui.start();
+		await terminal.waitForRender();
+
+		assert.ok(terminal.getViewport().some((line) => line.includes("first")));
+		assert.ok(terminal.getViewport().some((line) => line.includes("second")));
+		assert.ok(terminal.getViewport().some((line) => line.includes("third")));
+
+		tui.clear();
+		tui.requestRender();
+		await terminal.waitForRender();
+
+		const viewport = terminal.getViewport();
+		assert.ok(!viewport.some((line) => line.includes("first")), "first line should be cleared");
+		assert.ok(!viewport.some((line) => line.includes("second")), "second line should be cleared");
+		assert.ok(!viewport.some((line) => line.includes("third")), "third line should be cleared");
+
+		tui.stop();
+	});
+});