docs: add XML documentation and ConfigManager implementation plans

Add comprehensive XML documentation (param/returns tags) across 132 source
files to improve IntelliSense and API discoverability. Include ConfigManager
design documents and implementation plans for phases 1-9.

NEW/src/JdeScoping.DataSync/Telemetry/DataSyncMetrics.cs

@@ -18,6 +18,7 @@ public class DataSyncMetrics
     /// <summary>
     /// Initializes a new instance of the <see cref="DataSyncMetrics"/> class.
     /// </summary>
+    /// <param name="meterFactory">The meter factory for creating metrics.</param>
     public DataSyncMetrics(IMeterFactory meterFactory)
     {
         var meter = meterFactory.Create("JdeScoping.DataSync");
@@ -61,6 +62,8 @@ public class DataSyncMetrics
     /// <summary>
     /// Records that a sync operation has started.
     /// </summary>
+    /// <param name="tableName">The name of the table being synced.</param>
+    /// <param name="updateType">The type of update (e.g., Mass, Daily, Hourly).</param>
     public void RecordOperationStarted(string tableName, string updateType)
     {
         _operationsStarted.Add(1,
@@ -71,6 +74,10 @@ public class DataSyncMetrics
     /// <summary>
     /// Records that a sync operation completed successfully.
     /// </summary>
+    /// <param name="tableName">The name of the table being synced.</param>
+    /// <param name="updateType">The type of update (e.g., Mass, Daily, Hourly).</param>
+    /// <param name="recordCount">The number of records processed.</param>
+    /// <param name="durationSeconds">The operation duration in seconds.</param>
     public void RecordOperationCompleted(string tableName, string updateType, long recordCount, double durationSeconds)
     {
         var tags = new KeyValuePair<string, object?>[]
@@ -87,6 +94,8 @@ public class DataSyncMetrics
     /// <summary>
     /// Records that a sync operation failed.
     /// </summary>
+    /// <param name="tableName">The name of the table being synced.</param>
+    /// <param name="updateType">The type of update (e.g., Mass, Daily, Hourly).</param>
     public void RecordOperationFailed(string tableName, string updateType)
     {
         _operationsFailed.Add(1,
@@ -105,6 +114,9 @@ public class DataSyncMetrics
     /// <summary>
     /// Records completion of a sync cycle.
     /// </summary>
+    /// <param name="successCount">Number of successful operations in the cycle.</param>
+    /// <param name="failedCount">Number of failed operations in the cycle.</param>
+    /// <param name="durationSeconds">The cycle duration in seconds.</param>
     public void RecordCycleCompleted(int successCount, int failedCount, double durationSeconds)
     {
         _cyclesCompleted.Add(1,