S3.2: hand-placed 12x12 pixel icon set replaces lucide and reicon

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/unit/pixel-icons.test.ts

@@ -0,0 +1,13 @@
+import { expect, test } from "vitest";
+import { PIXEL_ICONS } from "../../src/renderer/src/shared/pixel-icons";
+
+test("every icon is a 12x12 bitmap of lit and dark pixels, and no two icons are the same", () => {
+  for (const [name, bitmap] of Object.entries(PIXEL_ICONS)) {
+    const rows = bitmap.split(" ");
+    expect(rows, name).toHaveLength(12);
+    for (const row of rows) expect(row, name).toMatch(/^[#.]{12}$/);
+    expect(bitmap.includes("#"), name).toBe(true);
+  }
+  const bitmaps = Object.values(PIXEL_ICONS);
+  expect(new Set(bitmaps).size).toBe(bitmaps.length);
+});