feat(config): add DexJobOptions configuration system and update placeholder pattern

- Add SectionName constant to DexJobOptions
- Update placeholder pattern to {#INT#BATCH_ID}
- Add DexJob configuration section to appsettings.json
- Add IConfiguration parameter to DependencyInjection for options binding
- Add Microsoft.Extensions.Options.ConfigurationExtensions package for .NET Framework 4.8
- Improve code documentation and move class into namespace

ECMJobRunner.Application/DependencyInjection.cs

@@ -1,5 +1,7 @@
+using ECMJobRunner.Application.Common.Options;
 using ECMJobRunner.Application.Profiles.Commands.Behaviors;
 using MediatR;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using ReC.Client;
 using System.Reflection;
@@ -17,8 +19,9 @@ namespace ECMJobRunner.Application
         /// </summary>
         /// <param name="services">The service collection</param>
         /// <param name="recClientApiUrl">The base URL for the ReC client API</param>
+        /// <param name="configuration">The application configuration</param>
         /// <returns>The service collection for chaining</returns>
-        public static IServiceCollection AddJobRunnerServices(this IServiceCollection services, string recClientApiUrl)
+        public static IServiceCollection AddJobRunnerServices(this IServiceCollection services, string recClientApiUrl, IConfiguration configuration)
         {
             var assembly = Assembly.GetExecutingAssembly();
 
@@ -36,6 +39,9 @@ namespace ECMJobRunner.Application
                 opt.LogSuccessfulRequests = true;
             });
 
+            // Configure DexJobOptions from appsettings.json
+            services.Configure<DexJobOptions>(configuration.GetSection(DexJobOptions.SectionName));
+
             // Register pipeline behaviors in execution order
             // Order matters: MainQuery -> CheckQuery -> ReCRequest
             services.AddTransient(typeof(IPipelineBehavior<,>), typeof(JobExceptionHandlingBehavior<,>));