app: add code for macOS and Windows apps under 'app' (#12933)

* app: add code for macOS and Windows apps under 'app'

* app: add readme

* app: windows and linux only for now

* ci: fix ui CI validation

---------

Co-authored-by: jmorganca <jmorganca@gmail.com>

app/auth/connect.go

@@ -0,0 +1,26 @@
+//go:build windows || darwin
+
+package auth
+
+import (
+	"encoding/base64"
+	"fmt"
+	"net/url"
+	"os"
+
+	"github.com/ollama/ollama/auth"
+)
+
+// BuildConnectURL generates the connect URL with the public key and device name
+func BuildConnectURL(baseURL string) (string, error) {
+	pubKey, err := auth.GetPublicKey()
+	if err != nil {
+		return "", fmt.Errorf("failed to get public key: %w", err)
+	}
+
+	encodedKey := base64.RawURLEncoding.EncodeToString([]byte(pubKey))
+	hostname, _ := os.Hostname()
+	encodedDevice := url.QueryEscape(hostname)
+
+	return fmt.Sprintf("%s/connect?name=%s&key=%s&launch=true", baseURL, encodedDevice, encodedKey), nil
+}