refactor: Extract ProfileWorker into modular components

- Create ProfileWorker namespace with 4 separate components
- ProfileWorker.cs: BackgroundService orchestrator with IOptions support
- ProfileWorkerOptions.cs: Configuration model with validation
- ProfileCache.cs: Thread-safe cache using composition pattern
- DependencyInjection.cs: Service registration with IValidateOptions

Benefits:
- Separation of concerns (orchestration, config, state, DI)
- IOptions pattern for appsettings.json configuration
- Startup validation for configuration errors
- Better testability and maintainability

ECMJobRunner.WebCron/ProfileWorker/ProfileWorker.cs

@@ -0,0 +1,39 @@
+using Microsoft.Extensions.Options;
+
+namespace ECMJobRunner.WebCron.ProfileWorker;
+
+public class ProfileWorker(
+    ILogger<ProfileWorker> Logger, 
+    IServiceScopeFactory ScopeFactory,
+    IOptions<ProfileWorkerOptions> Options) : BackgroundService
+{
+    private readonly ProfileWorkerOptions _options = Options.Value;
+
+    private int _workCount = 0;
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            _workCount++;
+            if (Logger.IsEnabled(LogLevel.Information))
+            {
+                Logger.LogInformation("Worker running {workCount} at: {time}", _workCount, DateTimeOffset.Now);
+            }
+
+            try
+            {
+                // Create a scope to resolve scoped services (ISQLExecutor used by MediatR pipeline)
+                using var scope = ScopeFactory.CreateScope();
+                var work = scope.ServiceProvider.GetRequiredService<ProfileWork>();
+                await work.ExecuteAsync(stoppingToken);
+            }
+            catch (Exception ex)
+            {
+                Logger.LogError(ex, "An unexpected error occurred in ProfileWorker. Work count: {workCount}", _workCount);
+            }
+
+            await Task.Delay(_options.IntervalMS, stoppingToken);
+        }
+    }
+}