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/store/schema_test.go

@@ -0,0 +1,60 @@
+//go:build windows || darwin
+
+package store
+
+import (
+	"path/filepath"
+	"testing"
+)
+
+func TestSchemaVersioning(t *testing.T) {
+	tmpDir := t.TempDir()
+	// Override legacy config path to avoid migration logs
+	oldLegacyConfigPath := legacyConfigPath
+	legacyConfigPath = filepath.Join(tmpDir, "config.json")
+	defer func() { legacyConfigPath = oldLegacyConfigPath }()
+
+	t.Run("new database has correct schema version", func(t *testing.T) {
+		dbPath := filepath.Join(tmpDir, "new_db.sqlite")
+		db, err := newDatabase(dbPath)
+		if err != nil {
+			t.Fatalf("failed to create database: %v", err)
+		}
+		defer db.Close()
+
+		// Check schema version
+		version, err := db.getSchemaVersion()
+		if err != nil {
+			t.Fatalf("failed to get schema version: %v", err)
+		}
+
+		if version != currentSchemaVersion {
+			t.Errorf("expected schema version %d, got %d", currentSchemaVersion, version)
+		}
+	})
+
+	t.Run("can update schema version", func(t *testing.T) {
+		dbPath := filepath.Join(tmpDir, "update_db.sqlite")
+		db, err := newDatabase(dbPath)
+		if err != nil {
+			t.Fatalf("failed to create database: %v", err)
+		}
+		defer db.Close()
+
+		// Set a different version
+		testVersion := 42
+		if err := db.setSchemaVersion(testVersion); err != nil {
+			t.Fatalf("failed to set schema version: %v", err)
+		}
+
+		// Verify it was updated
+		version, err := db.getSchemaVersion()
+		if err != nil {
+			t.Fatalf("failed to get schema version: %v", err)
+		}
+
+		if version != testVersion {
+			t.Errorf("expected schema version %d, got %d", testVersion, version)
+		}
+	})
+}