fix: harden operations and configuration recovery

internal/shell/shell_test.go

@@ -296,6 +296,27 @@ func TestShellTargetContract(t *testing.T) {
 				assertState(t, a, activeProfile(), target.Drifted)
 			})
 
+			t.Run("drifted-environment-refuses-destructive-restore", func(t *testing.T) {
+				a := newAdapter(t, shellName, nil)
+				if result := a.SetDesired(context.Background(), true, activeProfile()); result.Err != nil {
+					t.Fatal(result.Err)
+				}
+				changed := "export HTTP_PROXY='http://user-change.example:8080'\n"
+				if err := os.WriteFile(a.EnvironmentPath(), []byte(changed), 0o600); err != nil {
+					t.Fatal(err)
+				}
+				result := a.SetDesired(context.Background(), false, nil)
+				if result.Err == nil || result.Inspection.State != target.Drifted {
+					t.Fatalf("unsafe restore = %#v", result)
+				}
+				if got := readFile(t, a.EnvironmentPath()); got != changed {
+					t.Fatalf("drifted environment overwritten:\n%s", got)
+				}
+				if _, err := os.Stat(a.RecoveryPath()); err != nil {
+					t.Fatalf("recovery metadata removed after refused restore: %v", err)
+				}
+			})
+
 			t.Run("validation-and-redaction", func(t *testing.T) {
 				fs := &failingFS{FileSystem: shell.OSFileSystem{}, failWrite: true}
 				a := newAdapterWithFS(t, shellName, nil, fs)