fix(coding-agent): make tests keybinding-agnostic

Reset global editor keybindings to defaults in beforeEach for
session-selector-rename and tree-selector tests. Pass
KeybindingsManager.inMemory() to SessionSelectorComponent in tests
to avoid reading user keybindings.json.

Closes #2360

packages/coding-agent/test/tree-selector.test.ts

@@ -1,4 +1,5 @@
-import { beforeAll, describe, expect, test } from "vitest";
+import { DEFAULT_EDITOR_KEYBINDINGS, EditorKeybindingsManager, setEditorKeybindings } from "@mariozechner/pi-tui";
+import { beforeAll, beforeEach, describe, expect, test } from "vitest";
 import type {
 	ModelChangeEntry,
 	SessionEntry,
@@ -12,6 +13,11 @@ beforeAll(() => {
 	initTheme("dark");
 });
 
+beforeEach(() => {
+	// Ensure test isolation: editor keybindings are a global singleton
+	setEditorKeybindings(new EditorKeybindingsManager(DEFAULT_EDITOR_KEYBINDINGS));
+});
+
 // Helper to create a user message entry
 function userMessage(id: string, parentId: string | null, content: string): SessionMessageEntry {
 	return {