Give AgentCompany its own face: the pixel office tower icon

A new icon generated for the brand: an isometric pixel-art office building
with warm lit windows and the app's violet-blue accent wall on deep indigo -
the office floor is the product's signature, now it is the identity too.
The generated artwork is rebuilt into a clean 1024 square master
(resources/icon.png, Linux and the packaged base), a Big Sur rounded
variant with transparent corners for macOS (icon-mac.png), and a
multi-size Windows icon.ico (16-256). electron-builder wires each platform
to its variant, the icon ships inside the package, and Windows/Linux
windows carry it at runtime including dev. Verified by extracting the icon
back out of a packaged AgentCompany.exe.

src/main/app/create-window.ts

@@ -15,6 +15,9 @@ export function createMainWindow(options: CreateWindowOptions): BrowserWindow {
     minWidth: 980,
     minHeight: 700,
     title: "AgentCompany",
+    // macOS takes the window image from the app bundle; Windows and Linux
+    // want it on the window itself (dev runs included).
+    ...(process.platform === "darwin" ? {} : { icon: join(__dirname, "../../resources/icon.png") }),
     show: false,
     titleBarStyle: process.platform === "darwin" ? "hiddenInset" : "hidden",
     webPreferences: {