Rename session from /resume session list (#863)

* Add session renaming in interactive mode resume picker

Session list now displays last message timestamp as modified time
instead of file mtime. Ctrl+N enters rename mode in the interactive
resume picker, allowing quick session renaming without leaving the
selector. Rename hint is shown only in interactive mode, not in the
CLI --resume picker./

* Add docs entry for renaming in picker

* Update shortcut to ctrl+r for session renaming

packages/coding-agent/test/session-selector-rename.test.ts

@@ -0,0 +1,101 @@
+import { beforeAll, describe, expect, it, vi } from "vitest";
+import type { SessionInfo } from "../src/core/session-manager.js";
+import { SessionSelectorComponent } from "../src/modes/interactive/components/session-selector.js";
+import { initTheme } from "../src/modes/interactive/theme/theme.js";
+
+async function flushPromises(): Promise<void> {
+	await new Promise<void>((resolve) => {
+		setImmediate(resolve);
+	});
+}
+
+function makeSession(overrides: Partial<SessionInfo> & { id: string }): SessionInfo {
+	return {
+		path: overrides.path ?? `/tmp/${overrides.id}.jsonl`,
+		id: overrides.id,
+		cwd: overrides.cwd ?? "",
+		name: overrides.name,
+		created: overrides.created ?? new Date(0),
+		modified: overrides.modified ?? new Date(0),
+		messageCount: overrides.messageCount ?? 1,
+		firstMessage: overrides.firstMessage ?? "hello",
+		allMessagesText: overrides.allMessagesText ?? "hello",
+	};
+}
+
+// Kitty keyboard protocol encoding for Ctrl+R
+const CTRL_R = "\x1b[114;5u";
+
+describe("session selector rename", () => {
+	beforeAll(() => {
+		initTheme("dark");
+	});
+
+	it("shows rename hint in interactive /resume picker configuration", async () => {
+		const sessions = [makeSession({ id: "a" })];
+		const selector = new SessionSelectorComponent(
+			async () => sessions,
+			async () => [],
+			() => {},
+			() => {},
+			() => {},
+			() => {},
+			{ showRenameHint: true },
+		);
+		await flushPromises();
+
+		const output = selector.render(120).join("\n");
+		expect(output).toContain("ctrl+r");
+		expect(output).toContain("rename");
+	});
+
+	it("does not show rename hint in --resume picker configuration", async () => {
+		const sessions = [makeSession({ id: "a" })];
+		const selector = new SessionSelectorComponent(
+			async () => sessions,
+			async () => [],
+			() => {},
+			() => {},
+			() => {},
+			() => {},
+			{ showRenameHint: false },
+		);
+		await flushPromises();
+
+		const output = selector.render(120).join("\n");
+		expect(output).not.toContain("ctrl+r");
+		expect(output).not.toContain("rename");
+	});
+
+	it("enters rename mode on Ctrl+R and submits with Enter", async () => {
+		const sessions = [makeSession({ id: "a", name: "Old" })];
+		const renameSession = vi.fn(async () => {});
+
+		const selector = new SessionSelectorComponent(
+			async () => sessions,
+			async () => [],
+			() => {},
+			() => {},
+			() => {},
+			() => {},
+			{ renameSession, showRenameHint: true },
+		);
+		await flushPromises();
+
+		selector.getSessionList().handleInput(CTRL_R);
+		await flushPromises();
+
+		// Rename mode layout
+		const output = selector.render(120).join("\n");
+		expect(output).toContain("Rename Session");
+		expect(output).not.toContain("Resume Session");
+
+		// Type and submit
+		selector.handleInput("X");
+		selector.handleInput("\r");
+		await flushPromises();
+
+		expect(renameSession).toHaveBeenCalledTimes(1);
+		expect(renameSession).toHaveBeenCalledWith(sessions[0]!.path, "XOld");
+	});
+});