feat: add command palette functionality and shortcuts

- Implemented command palette with keyboard shortcut (⌘K) for opening.
- Added commands for opening, closing, setting query, and selecting items in the command palette.
- Created tests for command palette commands and input handling.
- Enhanced layer actions with functions for adding, grouping, and deleting layers.
- Updated UI components to integrate command palette and shortcuts.

commands/palette.test.ts

@@ -0,0 +1,40 @@
+import { describe, expect, test } from "bun:test";
+import { createInitialAppState } from "@editor/initial-state";
+import {
+  commandPaletteCloseCommand,
+  commandPaletteOpenCommand,
+  commandPaletteSetQueryCommand,
+  commandPaletteSetSelectedIndexCommand,
+} from "./palette";
+
+describe("command palette commands", () => {
+  test("opens with a reset query and selection", () => {
+    const initial = commandPaletteSetQueryCommand.execute({ state: createInitialAppState("Test") }, { query: "brush" });
+    const next = commandPaletteOpenCommand.execute({ state: initial }, undefined);
+
+    expect(next.editor.commandPalette).toEqual({ open: true, query: "", selectedIndex: 0 });
+  });
+
+  test("sets query and returns selected item to the first result", () => {
+    const opened = commandPaletteOpenCommand.execute({ state: createInitialAppState("Test") }, { query: "layer", selectedIndex: 4 });
+    const next = commandPaletteSetQueryCommand.execute({ state: opened }, { query: "zoom" });
+
+    expect(next.editor.commandPalette).toEqual({ open: true, query: "zoom", selectedIndex: 0 });
+  });
+
+  test("clamps selected index to a non-negative integer", () => {
+    const opened = commandPaletteOpenCommand.execute({ state: createInitialAppState("Test") }, undefined);
+    const fractional = commandPaletteSetSelectedIndexCommand.execute({ state: opened }, { selectedIndex: 3.8 });
+    const negative = commandPaletteSetSelectedIndexCommand.execute({ state: opened }, { selectedIndex: -1 });
+
+    expect(fractional.editor.commandPalette.selectedIndex).toBe(3);
+    expect(negative.editor.commandPalette.selectedIndex).toBe(0);
+  });
+
+  test("closes and clears transient palette text", () => {
+    const opened = commandPaletteOpenCommand.execute({ state: createInitialAppState("Test") }, { query: "debug", selectedIndex: 2 });
+    const next = commandPaletteCloseCommand.execute({ state: opened }, undefined);
+
+    expect(next.editor.commandPalette).toEqual({ open: false, query: "", selectedIndex: 0 });
+  });
+});