feat: Add Sandbox Inspection and Debugging Commands (#261)

* feat: add sandbox DX commands

* fix: Linter errors

* fix: Sandbox deny log parsing

* fix: Sandbox docs

* refactor: Maintain SSOT across pkg dependencies

* fix: Linter errors

cmd/sandbox/sandbox.go

@@ -0,0 +1,26 @@
+// Package sandbox implements the `pmg sandbox` command subtree.
+//
+// This is the ONLY package permitted to import internal/ui for rendering
+// sandbox diagnostics. The sandbox package produces structured probe
+// results; presentation lives here.
+package sandbox
+
+import "github.com/spf13/cobra"
+
+// NewCommand returns the `pmg sandbox` parent command.
+func NewCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "sandbox",
+		Short: "Inspect and manage PMG sandbox configuration",
+		Long:  "Tools for diagnosing the host sandbox environment and (in future PRs) managing sandbox profiles.",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return cmd.Help()
+		},
+	}
+
+	cmd.AddCommand(NewDoctorCommand())
+	cmd.AddCommand(NewProfileCommand())
+	cmd.AddCommand(NewExplainCommand())
+	cmd.AddCommand(NewViolationsCommand())
+	return cmd
+}