Revert "fix(http): propagate cross-tenant context in HTTP auth middleware (#427)"

This reverts commit 39b7c689f2.

internal/http/auth.go

@@ -289,17 +289,14 @@ func requireAuth(minRole permissions.Role, next http.HandlerFunc) http.HandlerFu
 		}
 		if auth.CrossTenant && auth.TenantID != uuid.Nil {
 			// Cross-tenant admin with tenant scope: filter data by chosen tenant
-			ctx = store.WithCrossTenant(ctx)
 			ctx = store.WithTenantID(ctx, auth.TenantID)
 			slog.Debug("security.http_auth_resolved",
 				"path", r.URL.Path,
 				"role", string(auth.Role),
-				"cross_tenant", true,
 				"tenant_scope", auth.TenantID.String(),
 			)
 		} else if auth.CrossTenant {
-			// Cross-tenant admin without scope: default to MasterTenantID.
-			ctx = store.WithCrossTenant(ctx)
+			// Auto-scope to MasterTenantID so all operations use a concrete tenant.
 			ctx = store.WithTenantID(ctx, store.MasterTenantID)
 			slog.Debug("security.http_auth_resolved",
 				"path", r.URL.Path,
@@ -370,7 +367,6 @@ func requireAuthBearer(minRole permissions.Role, bearer string, w http.ResponseW
 		ctx = store.WithUserID(ctx, userID)
 	}
 	if auth.CrossTenant {
-		ctx = store.WithCrossTenant(ctx)
 		ctx = store.WithTenantID(ctx, store.MasterTenantID)
 	} else if auth.TenantID != uuid.Nil {
 		ctx = store.WithTenantID(ctx, auth.TenantID)