[V3] App icon badge

[popaprozac]

Is your feature request related to a problem? Please describe.

Tauri and Electron allow setting a badge on the app icon.

Tauri
https://tauri.app/reference/javascript/api/namespacewindow/#setbadgecount
https://tauri.app/reference/javascript/api/namespacewindow/#setbadgelabel

Electron
https://www.electronjs.org/docs/latest/api/dock#docksetbadgetext-macos

Describe the solution you'd like

Expose an app.SetBadge(value string) method or similar to set an app badge on the dock icon.

Describe alternatives you've considered

Import and use DarwinKit

Example of my current usage (badgeservice_darwin.go):

package main

import "github.com/progrium/darwinkit/macos/appkit"

type BadgeService struct{}

func (g *BadgeService) SetBadge(value string) {
	app := appkit.Application_SharedApplication()
	dockTile := app.DockTile()

	if value == "" {
		dockTile.SetBadgeLabel("")
	} else {
		dockTile.SetBadgeLabel(value)
	}
}

Additional context

I am currently focused on macOS development so I haven't looked at Windows/Linux solutions yet (researching).
Relying on DarwinKit for this increases the app size to >35MB build and >25MB app.

[popaprozac]

Playing around on macOS this seems to work
application_darwin.go

// Set the application dock tile badge label
static void setBadgeLabel(const char *label) {
    NSString *nsLabel = nil;
	if (label != NULL) {
		nsLabel = [NSString stringWithUTF8String:label];
	}
	[[NSApp dockTile] setBadgeLabel:nsLabel];
	[[NSApp dockTile] display];
}
...
...
...
func (m *macosApp) setBadge(label string) {
	var cLabel *C.char
	if label != "" {
		cLabel = C.CString(label)
		defer C.free(unsafe.Pointer(cLabel))
	}
	C.setBadgeLabel(cLabel)
}

application.go

func (a *App) SetBadge(label string) {
	if a.impl != nil {
		if macApp, ok := a.impl.(*macosApp); ok {
			macApp.setBadge(label)
		}
	}
}

I will try to look at Windows and if it seems valuable I can open a PR.