feat: implement DEX job triggering commands with CQRS pattern

TriggeringDEXJobBatchCommand:
- Orchestrates batch job execution for a profile
- Creates unique 20-character timestamp-based batch ID
- Executes all SQL jobs sequentially for given profile ID
- Uses MediatR ISender to trigger individual job commands

TriggeringDEXJobCommand:
- Executes single DEX job with three-stage pipeline:
  1. Main Query: executes primary SQL with batch ID placeholder replacement
  2. Check Query: validates execution with return value check (> 0)
  3. ReC Request: invokes ReC API with batch ID reference
- Configurable error handling per stage via DexJobOptions
- Regex-based placeholder replacement for dynamic batch ID injection
- Returns Unit for void-like MediatR command pattern

Both commands include:
- Comprehensive XML documentation
- Primary constructor injection (modern C# syntax)
- Proper async/await with CancellationToken support
- Integration with ISQLExecutor and ReCClient abstractions

ECMJobRunner.Application/DEXJob/TriggeringDEXJobBatchCommand.cs

@@ -0,0 +1,73 @@
+using ECMJobRunner.Domain.Interfaces;
+using MediatR;
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace ECMJobRunner.Application.DEXJob
+{
+    /// <summary>
+    /// Command to trigger DEX job batch for a profile
+    /// Executes all SQL jobs associated with a profile ID
+    /// </summary>
+    public class TriggeringDEXJobBatchCommand : IRequest<Unit>
+    {
+        /// <summary>
+        /// Profile ID to trigger all associated SQL jobs
+        /// </summary>
+        public int ProfileId { get; set; }
+    }
+
+    /// <summary>
+    /// Handler for TriggeringDEXJobBatchCommand
+    /// Retrieves all SQL jobs for a profile and executes them sequentially
+    /// </summary>
+    public class TriggeringDEXJobBatchCommandHandler(IProfileSqlJobRepository jobRepo, ISender sender) 
+        : IRequestHandler<TriggeringDEXJobBatchCommand, Unit>
+    {
+        /// <summary>
+        /// Handles the TriggeringDEXJobBatchCommand
+        /// Creates a unique batch ID and triggers individual job commands
+        /// </summary>
+        /// <param name="request">The command containing the profile ID</param>
+        /// <param name="cancellationToken">Cancellation token</param>
+        /// <returns>Unit value indicating completion</returns>
+        public async Task<Unit> Handle(TriggeringDEXJobBatchCommand request, CancellationToken cancellationToken)
+        {
+            var jobs = await jobRepo.FindAsync(j => j.ProfileId == request.ProfileId, cancellationToken);
+
+            var batchId = CreateBatchId();
+
+            foreach (var job in jobs)
+            {
+                await sender.Send(new TriggeringDEXJobCommand
+                {
+                    Job = job,
+                    BatchId = batchId
+                }, cancellationToken);
+            }
+
+            return Unit.Value;
+        }
+
+        /// <summary>
+        /// Creates a unique batch ID based on current timestamp
+        /// </summary>
+        /// <returns>20-character timestamp string (yyyyMMddHHmmssfffffff truncated to 20 chars)</returns>
+        public static string CreateBatchId()
+        {
+            // Format: "yyyy"   : Year (4 digits)
+            //         "MM"     : Month (2 digits)
+            //         "dd"     : Day (2 digits)
+            //         "HH"     : Hour (24-hour format, 2 digits)
+            //         "mm"     : Minute (2 digits)
+            //         "ss"     : Second (2 digits)
+            //         "fffffff": Fractions of a second / 100-nanoseconds (7 digits)
+
+            string fullBatchId = DateTime.Now.ToString("yyyyMMddHHmmssfffffff");
+
+            // Limit to 20 characters as per specification
+            return fullBatchId.Substring(0, 20);
+        }
+    }
+}