fix: delete instance data and remove legacy shared workspace support

internal/api/files_test.go

@@ -449,7 +449,10 @@ func TestWorkspaceSafetyAndUpload(t *testing.T) {
 	if err := s.CreateUser(u, "unused"); err != nil {
 		t.Fatal(err)
 	}
-	root, e := a.openWorkspace(u)
+	if err := os.MkdirAll(filepath.Join(a.root, "workspaces/user/instances/one/home"), 0750); err != nil {
+		t.Fatal(err)
+	}
+	root, e := a.openWorkspace(u, "one")
 	if e != nil {
 		t.Fatal(e)
 	}
@@ -463,7 +466,7 @@ func TestWorkspaceSafetyAndUpload(t *testing.T) {
 	}
 	outside := t.TempDir()
 	os.WriteFile(filepath.Join(outside, "secret"), []byte("secret"), 0600)
-	if e = os.Symlink(outside, filepath.Join(a.root, "workspaces/user/files/link")); e != nil {
+	if e = os.Symlink(outside, filepath.Join(a.root, "workspaces/user/instances/one/home/link")); e != nil {
 		t.Fatal(e)
 	}
 	w := httptest.NewRecorder()