Rename app to Oikos (was oikos-desktop)

- Binary: oikos-desktop → Oikos
- Bundle: oikos-desktop.app → Oikos.app
- Install path: /Applications/Oikos.app
- Auto-update paths updated
- CI Linux binary renamed

cmd/desktop/main.go

@@ -604,12 +604,12 @@ func doUpdate(downloadURL string) error {
 		return fmt.Errorf("unzip: %w: %s", err, out)
 	}
 
-	newApp := filepath.Join(extractDir, "oikos-desktop.app")
+	newApp := filepath.Join(extractDir, "Oikos.app")
 	if _, err := os.Stat(newApp); err != nil {
 		return fmt.Errorf("extracted app not found: %w", err)
 	}
 
-	currentApp := "/Applications/oikos-desktop.app"
+	currentApp := "/Applications/Oikos.app"
 	if _, err := os.Stat(currentApp); os.IsNotExist(err) {
 		if exe, err := os.Executable(); err == nil {
 			currentApp = filepath.Dir(filepath.Dir(filepath.Dir(exe)))