Add integration tests for migration categories and execution

- Implemented MigrationCategoryTests to validate migration categorization for startup, release, seed, and data migrations.
- Added tests for edge cases, including null, empty, and whitespace migration names.
- Created StartupMigrationHostTests to verify the behavior of the migration host with real PostgreSQL instances using Testcontainers.
- Included tests for migration execution, schema creation, and handling of pending release migrations.
- Added SQL migration files for testing: creating a test table, adding a column, a release migration, and seeding data.

src/Cli/StellaOps.Cli/Services/ObservabilityClient.cs

@@ -9,6 +9,7 @@ using Microsoft.Extensions.Logging;
 using StellaOps.Auth.Abstractions;
 using StellaOps.Auth.Client;
 using StellaOps.Cli.Configuration;
+using StellaOps.Cli.Extensions;
 using StellaOps.Cli.Services.Models;
 
 namespace StellaOps.Cli.Services;
@@ -170,12 +171,10 @@ internal sealed class ObservabilityClient : IObservabilityClient
             }
         }
 
-        var result = await tokenClient.GetTokenAsync(
-            new StellaOpsTokenRequest { Scopes = ["obs:read"] },
-            cancellationToken).ConfigureAwait(false);
-
-        if (result.IsSuccess)
+        try
         {
+            var result = await tokenClient.GetAccessTokenAsync(StellaOpsScopes.ObservabilityRead, cancellationToken).ConfigureAwait(false);
+
             lock (tokenSync)
             {
                 cachedAccessToken = result.AccessToken;
@@ -183,9 +182,11 @@ internal sealed class ObservabilityClient : IObservabilityClient
             }
             return result.AccessToken;
         }
-
-        logger.LogWarning("Token acquisition failed: {Error}", result.Error);
-        return null;
+        catch (Exception ex)
+        {
+            logger.LogWarning(ex, "Token acquisition failed");
+            return null;
+        }
     }
 
     // CLI-OBS-52-001: Trace retrieval