feat: Implement IsolatedReplayContext for deterministic audit replay

- Added IsolatedReplayContext class to provide an isolated environment for replaying audit bundles without external calls.
- Introduced methods for initializing the context, verifying input digests, and extracting inputs for policy evaluation.
- Created supporting interfaces and options for context configuration.

feat: Create ReplayExecutor for executing policy re-evaluation and verdict comparison

- Developed ReplayExecutor class to handle the execution of replay processes, including input verification and verdict comparison.
- Implemented detailed drift detection and error handling during replay execution.
- Added interfaces for policy evaluation and replay execution options.

feat: Add ScanSnapshotFetcher for fetching scan data and snapshots

- Introduced ScanSnapshotFetcher class to retrieve necessary scan data and snapshots for audit bundle creation.
- Implemented methods to fetch scan metadata, advisory feeds, policy snapshots, and VEX statements.
- Created supporting interfaces for scan data, feed snapshots, and policy snapshots.

src/Cli/StellaOps.Cli/Commands/CommandHandlers.Audit.cs

@@ -12,6 +12,7 @@ using Microsoft.Extensions.Logging;
 using StellaOps.AuditPack.Models;
 using StellaOps.AuditPack.Services;
 using StellaOps.Cli.Configuration;
+using StellaOps.Cli.Services;
 using StellaOps.Cli.Telemetry;
 using Spectre.Console;
 
@@ -153,9 +154,9 @@ internal static partial class CommandHandlers
         }
 
         // Enforce offline mode if requested
-        if (offline && !OfflineModeGuard.IsNetworkAllowed(options, "audit replay", forceOffline: true))
+        if (offline)
         {
-            // This is expected - we're in offline mode
+            OfflineModeGuard.IsOffline = true;
             logger.LogDebug("Running in offline mode as requested.");
         }
 
@@ -462,7 +463,7 @@ public sealed record ImportOptions
 /// </summary>
 public interface IAuditPackImporter
 {
-    Task<AuditPack> ImportAsync(string bundlePath, ImportOptions options, CancellationToken ct = default);
+    Task<StellaOps.AuditPack.Models.AuditPack> ImportAsync(string bundlePath, ImportOptions options, CancellationToken ct = default);
 }
 
 /// <summary>
@@ -470,5 +471,5 @@ public interface IAuditPackImporter
 /// </summary>
 public interface IAuditPackReplayer
 {
-    Task<AuditReplayResult> ReplayAsync(AuditPack pack, ReplayOptions options, CancellationToken ct = default);
+    Task<AuditReplayResult> ReplayAsync(StellaOps.AuditPack.Models.AuditPack pack, ReplayOptions options, CancellationToken ct = default);
 }