feat(ui): refresh branding and account identity copying

Replace every active application icon asset with the new high-resolution artwork, including transparent PNG, complete Windows ICO sizes, and the documentation screenshot.

Turn populated username and email cells into non-selectable copy actions backed by validated native Electron clipboard IPC while keeping empty cells and row interactions unchanged.

tests/app-icon.test.ts

@@ -1,3 +1,4 @@
+import fs from "node:fs";
 import path from "node:path";
 import { describe, expect, it } from "vitest";
 import { resolveAppIconPath } from "../src/main/app-icon";
@@ -14,4 +15,20 @@ describe("application icon path", () => {
       path.join("C:\\repo", "assets", "app_icon.ico")
     );
   });
+
+  it("ships a high-resolution transparent PNG and complete Windows icon sizes", () => {
+    const png = fs.readFileSync(path.resolve("assets/app_icon.png"));
+    expect(png.subarray(0, 8)).toEqual(Buffer.from([137, 80, 78, 71, 13, 10, 26, 10]));
+    expect(png.readUInt32BE(16)).toBeGreaterThanOrEqual(1024);
+    expect(png.readUInt32BE(20)).toBeGreaterThanOrEqual(1024);
+    expect([4, 6]).toContain(png[25]);
+
+    const ico = fs.readFileSync(path.resolve("assets/app_icon.ico"));
+    const frameCount = ico.readUInt16LE(4);
+    const sizes = Array.from({ length: frameCount }, (_, index) => {
+      const offset = 6 + index * 16;
+      return ico[offset] || 256;
+    });
+    expect(sizes).toEqual(expect.arrayContaining([16, 32, 48, 256]));
+  });
 });