feat: squircle dock icon for macOS dev mode

macOS only applies the squircle mask to packaged .app bundles. For dev
mode, generate a pre-masked icon-dock.png via Swift/AppKit at launch
and set it with app.dock.setIcon(). Silently skipped on non-macOS.

packages/desktop/package.json

@@ -5,7 +5,7 @@
   "main": "dist/main.js",
   "scripts": {
     "build:ts": "tsc",
-    "dev": "tsc && electron .",
+    "dev": "mkdir -p build && cp ../../icon.png build/icon.png && node -e \"try{require('child_process').execSync('swift scripts/gen-dock-icon.swift',{stdio:'inherit'})}catch(e){}\" && tsc && electron .",
     "prebuild": "mkdir -p build && cp ../../icon.png build/icon.png",
     "build": "tsc && electron-builder",
     "clean": "rm -rf dist dist-electron"

packages/desktop/scripts/gen-dock-icon.swift

@@ -0,0 +1,21 @@
+// Generates a squircle-masked dock icon for macOS dev mode.
+// macOS only applies the squircle mask to packaged .app bundles,
+// so app.dock.setIcon() needs a pre-masked PNG.
+
+import AppKit
+
+let src = NSImage(contentsOfFile: "build/icon.png")!
+let size = src.size
+let out = NSImage(size: size)
+
+out.lockFocus()
+let radius = size.width * 0.2237
+let path = NSBezierPath(roundedRect: NSRect(origin: .zero, size: size), xRadius: radius, yRadius: radius)
+path.addClip()
+src.draw(in: NSRect(origin: .zero, size: size), from: NSRect(origin: .zero, size: size), operation: .sourceOver, fraction: 1.0)
+out.unlockFocus()
+
+let tiff = out.tiffRepresentation!
+let rep = NSBitmapImageRep(data: tiff)!
+let png = rep.representation(using: .png, properties: [:])!
+try! png.write(to: URL(fileURLWithPath: "build/icon-dock.png"))

packages/desktop/src/main.ts

@@ -513,6 +513,16 @@ if (!gotTheLock) {
   // ─── App Lifecycle ──────────────────────────────────────────────────────────
 
   app.whenReady().then(async () => {
+    // Set dock icon on macOS (overrides default Electron icon in dev mode)
+    if (process.platform === 'darwin' && app.dock) {
+      const dockIcon = path.join(__dirname, '..', 'build', 'icon-dock.png');
+      const fallbackIcon = path.join(__dirname, '..', 'build', 'icon.png');
+      const iconPath = fs.existsSync(dockIcon) ? dockIcon : fallbackIcon;
+      if (fs.existsSync(iconPath)) {
+        app.dock.setIcon(iconPath);
+      }
+    }
+
     // macOS application menu with "Change Instance"
     if (process.platform === 'darwin') {
       const appMenu = Menu.buildFromTemplate([