fix: resolve build errors in pass_mgr, pcexec, and safe-restart

- Fix Go syntax error: use BoolVar for --username flag instead of string
- Fix TypeScript type errors: filter undefined values from process.env
- Fix TypeScript type error: add type assertion for fetch response
- Add .gitignore to exclude node_modules and build outputs

pass_mgr/src/main.go

@@ -41,7 +41,6 @@ type Config struct {
 var (
 	workspaceDir string
 	agentID      string
-	username     string
 )
 
 func main() {
@@ -70,7 +69,8 @@ func main() {
 }
 
 func getCmd() *cobra.Command {
-	return &cobra.Command{
+	var showUsername bool
+	cmd := &cobra.Command{
 		Use:   "get [key]",
 		Short: "Get password for a key",
 		Args:  cobra.ExactArgs(1),
@@ -81,13 +81,15 @@ func getCmd() *cobra.Command {
 				fmt.Fprintf(os.Stderr, "Error: %v\n", err)
 				os.Exit(1)
 			}
-			if username {
+			if showUsername {
 				fmt.Println(user)
 			} else {
 				fmt.Println(password)
 			}
 		},
 	}
+	cmd.Flags().BoolVar(&showUsername, "username", false, "Show username instead of password")
+	return cmd
 }
 
 func generateCmd() *cobra.Command {