Add runtime abstraction and agent loop

Co-authored-by: codegirl007 <codegirl-007@users.noreply.github.com>

agentbox/internal/appspec/appspec_test.go

@@ -0,0 +1,28 @@
+package appspec
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestResolveDirectoryManifest(t *testing.T) {
+	directory := t.TempDir()
+	executable := filepath.Join(directory, "game")
+	if err := os.WriteFile(executable, []byte("binary"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	manifest := `{"command":"game","args":["--demo"],"window_title":"Demo"}`
+	if err := os.WriteFile(filepath.Join(directory, "agentbox.json"), []byte(manifest), 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	command, err := Resolve(directory)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if command.Path != executable || command.WindowTitle != "Demo" ||
+		len(command.Args) != 1 || command.Args[0] != "--demo" {
+		t.Fatalf("command = %#v", command)
+	}
+}