chore(webapp): downgrade SVE schedule-sync log in createBackgroundWorker to warn

Customer schedule-config failures (typically invalid cron) get rethrown
to the route handler as ServiceValidationError; that's a 4xx, not a
system bug. Split the SVE branch out and log at warn before rethrowing.
Non-SVE failures still log at error before being wrapped, mirroring
dac9c83's waitpointCompletionPacket.server.ts pattern so visibility
survives the SDK-level SVE filter.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: d-cs

apps/webapp/app/v3/services/createBackgroundWorker.server.ts

@@ -146,16 +146,27 @@ export class CreateBackgroundWorkerService extends BaseService {
       );
 
       if (schedulesError) {
+        if (schedulesError instanceof ServiceValidationError) {
+          // Customer schedule config (typically invalid cron). Surface to
+          // client via the rethrow; system returns gracefully.
+          logger.warn("Error syncing declarative schedules", {
+            error: schedulesError.message,
+            backgroundWorker,
+            environment,
+          });
+          throw schedulesError;
+        }
+
+        // Wrapping the underlying error into a ServiceValidationError below
+        // would otherwise hide it once the SDK-level filter drops SVEs; log at
+        // error so the underlying cause stays visible. Mirrors the
+        // waitpointCompletionPacket.server.ts pattern from dac9c83bd.
         logger.error("Error syncing declarative schedules", {
           error: schedulesError,
           backgroundWorker,
           environment,
         });
 
-        if (schedulesError instanceof ServiceValidationError) {
-          throw schedulesError;
-        }
-
         throw new ServiceValidationError("Error syncing declarative schedules");
       }