fix(rd21): guard career and job saves with durable revisions

JobTrackerApi/Program.cs

@@ -160,6 +160,7 @@ builder.Services.AddProblemDetails(options =>
         context.ProblemDetails.Extensions["traceId"] = context.HttpContext.TraceIdentifier;
 });
 builder.Services.AddExceptionHandler<AiUsageLimitExceptionHandler>();
+builder.Services.AddExceptionHandler<RevisionConflictExceptionHandler>();
 builder.Services.AddExceptionHandler<PdfRenderExceptionHandler>();
 builder.Services.AddOpenApi();
 var dataRoot = (builder.Configuration["Data:Root"] ?? "").Trim();