chore(webapp): downgrade SVE/OOE logs in api.v3.batches to warn

Customer-facing 422 paths now log at warn; only the 500 fall-through
escalates to Sentry. Rate-limit (BatchProcessingError 429) branch above
is unchanged.

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

Author: d-cs

apps/webapp/app/routes/api.v3.batches.ts

@@ -172,18 +172,26 @@ const { action, loader } = createActionApiRoute(
         );
       }
 
+      // Customer-facing validation/quota failures (invalid batch shape,
+      // entitlements exhausted). The handler returns 422 with the message;
+      // system handles it gracefully, no alert needed.
+      if (error instanceof ServiceValidationError) {
+        logger.warn("Create batch error", { error: error.message });
+        return json({ error: error.message }, { status: 422 });
+      }
+      if (error instanceof OutOfEntitlementError) {
+        logger.warn("Create batch error", { error: error.message });
+        return json({ error: error.message }, { status: 422 });
+      }
+
       logger.error("Create batch error", {
         error: {
           message: (error as Error).message,
           stack: (error as Error).stack,
         },
       });
 
-      if (error instanceof ServiceValidationError) {
-        return json({ error: error.message }, { status: 422 });
-      } else if (error instanceof OutOfEntitlementError) {
-        return json({ error: error.message }, { status: 422 });
-      } else if (error instanceof Error) {
+      if (error instanceof Error) {
         return json(
           { error: error.message },
           { status: 500, headers: { "x-should-retry": "false" } }