feat: add Reachability Center and Why Drawer components with tests

- Implemented ReachabilityCenterComponent for displaying asset reachability status with summary and filtering options.
- Added ReachabilityWhyDrawerComponent to show detailed reachability evidence and call paths.
- Created unit tests for both components to ensure functionality and correctness.
- Updated accessibility test results for the new components.

src/Concelier/__Libraries/StellaOps.Concelier.Storage.Postgres/SourceStateAdapter.cs

@@ -1,11 +1,11 @@
 using System;
 using System.Text.Json;
 using System.Collections.Generic;
-using MongoDB.Bson;
+using StellaOps.Concelier.Bson;
 using StellaOps.Concelier.Storage.Postgres.Models;
 using StellaOps.Concelier.Storage.Postgres.Repositories;
 using Contracts = StellaOps.Concelier.Storage.Contracts;
-using MongoContracts = StellaOps.Concelier.Storage.Mongo;
+using MongoContracts = StellaOps.Concelier.Storage;
 
 namespace StellaOps.Concelier.Storage.Postgres;
 
@@ -45,6 +45,7 @@ public sealed class PostgresSourceStateAdapter : MongoContracts.ISourceStateRepo
         }
 
         var cursor = string.IsNullOrWhiteSpace(state.Cursor) ? null : BsonDocument.Parse(state.Cursor);
+        var backoffUntil = TryParseBackoffUntil(state.Metadata);
         return new MongoContracts.SourceStateRecord(
             sourceName,
             Enabled: true,
@@ -53,7 +54,7 @@ public sealed class PostgresSourceStateAdapter : MongoContracts.ISourceStateRepo
             LastSuccess: state.LastSuccessAt,
             LastFailure: state.LastError is null ? null : state.LastSyncAt,
             FailCount: state.ErrorCount,
-            BackoffUntil: null,
+            BackoffUntil: backoffUntil,
             UpdatedAt: state.UpdatedAt,
             LastFailureReason: state.LastError);
     }
@@ -183,4 +184,32 @@ public sealed class PostgresSourceStateAdapter : MongoContracts.ISourceStateRepo
             return delta < TimeSpan.Zero ? DateTimeOffset.MinValue : DateTimeOffset.MaxValue;
         }
     }
+
+    private static DateTimeOffset? TryParseBackoffUntil(string? metadata)
+    {
+        if (string.IsNullOrWhiteSpace(metadata))
+        {
+            return null;
+        }
+
+        try
+        {
+            using var document = JsonDocument.Parse(metadata);
+            if (!document.RootElement.TryGetProperty("backoffUntil", out var backoffProperty))
+            {
+                return null;
+            }
+
+            if (backoffProperty.ValueKind == JsonValueKind.String
+                && DateTimeOffset.TryParse(backoffProperty.GetString(), out var parsed))
+            {
+                return parsed;
+            }
+        }
+        catch
+        {
+        }
+
+        return null;
+    }
 }