feat: IsFlag helper — cli.go now has zero string imports

core.IsFlag(arg) checks if an argument starts with a dash.
Cli.go no longer imports strings — all string ops via utils.go helpers.

Co-Authored-By: Virgil <virgil@lethean.io>

pkg/core/cli.go

@@ -16,7 +16,6 @@ package core
 import (
 	"io"
 	"os"
-	"strings"
 )
 
 // Cli is the CLI surface for the Core command tree.
@@ -89,7 +88,7 @@ func (cl *Cli) Run(args ...string) Result[any] {
 			} else {
 				opts = append(opts, Option{K: key, V: true})
 			}
-		} else if !strings.HasPrefix(arg, "-") {
+		} else if !IsFlag(arg) {
 			opts = append(opts, Option{K: "_arg", V: arg})
 		}
 	}

pkg/core/utils.go

@@ -31,6 +31,15 @@ func JoinPath(segments ...string) string {
 	return strings.Join(segments, "/")
 }
 
+// IsFlag returns true if the argument starts with a dash.
+//
+//	core.IsFlag("--verbose")  // true
+//	core.IsFlag("-v")         // true
+//	core.IsFlag("deploy")    // false
+func IsFlag(arg string) bool {
+	return strings.HasPrefix(arg, "-")
+}
+
 // FilterArgs removes empty strings and Go test runner flags from an argument list.
 //
 //	clean := core.FilterArgs(os.Args[1:])