test(pi-tui): add regression tests for loader, cancellable-loader, input

First test coverage for pi-tui components (8 tests):
- Loader: start() idempotency, dispose() cleanup, stop() safety
- CancellableLoader: abort on dispose, callback cleanup, signal state
- Input: paste buffer reset on focus loss, focused getter/setter

packages/pi-tui/src/components/__tests__/cancellable-loader.test.ts

@@ -0,0 +1,45 @@
+// pi-tui CancellableLoader component regression tests
+// Copyright (c) 2026 Jeremy McSpadden <jeremy@fluxlabs.net>
+
+import { describe, it, mock, beforeEach, afterEach } from "node:test";
+import assert from "node:assert/strict";
+import { CancellableLoader } from "../cancellable-loader.js";
+
+function makeMockTUI() {
+	return { requestRender: mock.fn() } as any;
+}
+
+describe("CancellableLoader", () => {
+	let loader: CancellableLoader;
+	let tui: ReturnType<typeof makeMockTUI>;
+
+	beforeEach(() => {
+		tui = makeMockTUI();
+	});
+
+	afterEach(() => {
+		loader?.dispose();
+	});
+
+	it("dispose() aborts the AbortController signal", () => {
+		loader = new CancellableLoader(tui, (s) => s, (s) => s, "test");
+		assert.equal(loader.aborted, false);
+		loader.dispose();
+		assert.equal(loader.aborted, true);
+	});
+
+	it("dispose() clears the onAbort callback", () => {
+		loader = new CancellableLoader(tui, (s) => s, (s) => s, "test");
+		loader.onAbort = () => {};
+		loader.dispose();
+		assert.equal(loader.onAbort, undefined);
+	});
+
+	it("signal is aborted after dispose()", () => {
+		loader = new CancellableLoader(tui, (s) => s, (s) => s, "test");
+		const signal = loader.signal;
+		assert.equal(signal.aborted, false);
+		loader.dispose();
+		assert.equal(signal.aborted, true);
+	});
+});

packages/pi-tui/src/components/__tests__/input.test.ts

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+// pi-tui Input component regression tests
+// Copyright (c) 2026 Jeremy McSpadden <jeremy@fluxlabs.net>
+
+import { describe, it } from "node:test";
+import assert from "node:assert/strict";
+import { Input } from "../input.js";
+
+describe("Input", () => {
+	it("paste buffer is cleared when focus is lost", () => {
+		const input = new Input();
+		input.focused = true;
+
+		// Simulate starting a paste (bracket paste start marker)
+		input.handleInput("\x1b[200~partial");
+
+		// Now lose focus mid-paste
+		input.focused = false;
+
+		// Regain focus — should not have stale paste state
+		input.focused = true;
+
+		// Typing normal text should work without paste buffer corruption
+		input.handleInput("hello");
+		assert.equal(input.getValue(), "hello");
+	});
+
+	it("focused getter/setter works correctly", () => {
+		const input = new Input();
+		assert.equal(input.focused, false);
+		input.focused = true;
+		assert.equal(input.focused, true);
+		input.focused = false;
+		assert.equal(input.focused, false);
+	});
+});

packages/pi-tui/src/components/__tests__/loader.test.ts

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+// pi-tui Loader component regression tests
+// Copyright (c) 2026 Jeremy McSpadden <jeremy@fluxlabs.net>
+
+import { describe, it, mock, beforeEach, afterEach } from "node:test";
+import assert from "node:assert/strict";
+import { Loader } from "../loader.js";
+
+function makeMockTUI() {
+	return { requestRender: mock.fn() } as any;
+}
+
+describe("Loader", () => {
+	let loader: Loader;
+	let tui: ReturnType<typeof makeMockTUI>;
+
+	beforeEach(() => {
+		tui = makeMockTUI();
+	});
+
+	afterEach(() => {
+		loader?.stop();
+	});
+
+	it("start() is idempotent — calling twice does not leak intervals", () => {
+		loader = new Loader(tui, (s) => s, (s) => s, "test");
+		// Constructor calls start() once, call it again
+		loader.start();
+		// stop() should clear the interval cleanly without orphaned timers
+		loader.stop();
+	});
+
+	it("dispose() stops the interval and nulls the TUI reference", () => {
+		loader = new Loader(tui, (s) => s, (s) => s, "test");
+		loader.dispose();
+		// After dispose, calling stop() again should be safe (no-op)
+		loader.stop();
+	});
+
+	it("stop() is safe to call multiple times", () => {
+		loader = new Loader(tui, (s) => s, (s) => s, "test");
+		loader.stop();
+		loader.stop();
+		loader.stop();
+	});
+});