Implement InMemory Transport Layer for StellaOps Router

- Added InMemoryTransportOptions class for configuration settings including timeouts and latency.
- Developed InMemoryTransportServer class to handle connections, frame processing, and event management.
- Created ServiceCollectionExtensions for easy registration of InMemory transport services.
- Established project structure and dependencies for InMemory transport library.
- Implemented comprehensive unit tests for endpoint discovery, connection management, request/response flow, and streaming capabilities.
- Ensured proper handling of cancellation, heartbeat, and hello frames within the transport layer.

src/Cli/StellaOps.Cli/Services/Models/MirrorBundleModels.cs

@@ -0,0 +1,249 @@
+using System;
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+
+namespace StellaOps.Cli.Services.Models;
+
+/// <summary>
+/// Air-gap mirror bundle format for offline operation with DSSE signature support.
+/// Maps to docs/schemas/mirror-bundle.schema.json
+/// </summary>
+internal sealed record MirrorBundle
+{
+    [JsonPropertyName("schemaVersion")]
+    public int SchemaVersion { get; init; } = 1;
+
+    [JsonPropertyName("generatedAt")]
+    public DateTimeOffset GeneratedAt { get; init; }
+
+    [JsonPropertyName("targetRepository")]
+    public string? TargetRepository { get; init; }
+
+    [JsonPropertyName("domainId")]
+    public required string DomainId { get; init; }
+
+    [JsonPropertyName("displayName")]
+    public string? DisplayName { get; init; }
+
+    [JsonPropertyName("exports")]
+    public required IReadOnlyList<MirrorBundleExport> Exports { get; init; }
+}
+
+internal sealed record MirrorBundleExport
+{
+    [JsonPropertyName("key")]
+    public required string Key { get; init; }
+
+    [JsonPropertyName("format")]
+    public required string Format { get; init; }
+
+    [JsonPropertyName("exportId")]
+    public required string ExportId { get; init; }
+
+    [JsonPropertyName("querySignature")]
+    public string? QuerySignature { get; init; }
+
+    [JsonPropertyName("createdAt")]
+    public required DateTimeOffset CreatedAt { get; init; }
+
+    [JsonPropertyName("artifactSizeBytes")]
+    public long? ArtifactSizeBytes { get; init; }
+
+    [JsonPropertyName("artifactDigest")]
+    public required string ArtifactDigest { get; init; }
+
+    [JsonPropertyName("consensusRevision")]
+    public string? ConsensusRevision { get; init; }
+
+    [JsonPropertyName("policyRevisionId")]
+    public string? PolicyRevisionId { get; init; }
+
+    [JsonPropertyName("policyDigest")]
+    public string? PolicyDigest { get; init; }
+
+    [JsonPropertyName("consensusDigest")]
+    public string? ConsensusDigest { get; init; }
+
+    [JsonPropertyName("scoreDigest")]
+    public string? ScoreDigest { get; init; }
+
+    [JsonPropertyName("sourceProviders")]
+    public IReadOnlyList<string>? SourceProviders { get; init; }
+
+    [JsonPropertyName("attestation")]
+    public MirrorAttestationDescriptor? Attestation { get; init; }
+}
+
+internal sealed record MirrorAttestationDescriptor
+{
+    [JsonPropertyName("predicateType")]
+    public required string PredicateType { get; init; }
+
+    [JsonPropertyName("rekorLocation")]
+    public string? RekorLocation { get; init; }
+
+    [JsonPropertyName("envelopeDigest")]
+    public string? EnvelopeDigest { get; init; }
+
+    [JsonPropertyName("signedAt")]
+    public DateTimeOffset? SignedAt { get; init; }
+}
+
+internal sealed record MirrorBundleSignature
+{
+    [JsonPropertyName("path")]
+    public string? Path { get; init; }
+
+    [JsonPropertyName("algorithm")]
+    public required string Algorithm { get; init; }
+
+    [JsonPropertyName("keyId")]
+    public required string KeyId { get; init; }
+
+    [JsonPropertyName("provider")]
+    public string? Provider { get; init; }
+
+    [JsonPropertyName("signedAt")]
+    public required DateTimeOffset SignedAt { get; init; }
+}
+
+internal sealed record MirrorBundleManifest
+{
+    [JsonPropertyName("schemaVersion")]
+    public int SchemaVersion { get; init; } = 1;
+
+    [JsonPropertyName("generatedAt")]
+    public DateTimeOffset GeneratedAt { get; init; }
+
+    [JsonPropertyName("domainId")]
+    public required string DomainId { get; init; }
+
+    [JsonPropertyName("displayName")]
+    public string? DisplayName { get; init; }
+
+    [JsonPropertyName("targetRepository")]
+    public string? TargetRepository { get; init; }
+
+    [JsonPropertyName("bundle")]
+    public required MirrorFileDescriptor Bundle { get; init; }
+
+    [JsonPropertyName("exports")]
+    public IReadOnlyList<MirrorBundleExport>? Exports { get; init; }
+}
+
+internal sealed record MirrorFileDescriptor
+{
+    [JsonPropertyName("path")]
+    public required string Path { get; init; }
+
+    [JsonPropertyName("sizeBytes")]
+    public required long SizeBytes { get; init; }
+
+    [JsonPropertyName("digest")]
+    public required string Digest { get; init; }
+
+    [JsonPropertyName("signature")]
+    public MirrorBundleSignature? Signature { get; init; }
+}
+
+/// <summary>
+/// Request model for creating a mirror bundle.
+/// </summary>
+internal sealed record MirrorCreateRequest
+{
+    /// <summary>
+    /// Domain identifier (e.g., "vex-advisories", "vulnerability-feeds", "policy-packs").
+    /// </summary>
+    public required string DomainId { get; init; }
+
+    /// <summary>
+    /// Human-readable display name for the bundle.
+    /// </summary>
+    public string? DisplayName { get; init; }
+
+    /// <summary>
+    /// Target OCI repository for this bundle.
+    /// </summary>
+    public string? TargetRepository { get; init; }
+
+    /// <summary>
+    /// Export format filter (e.g., "openvex", "csaf", "cyclonedx").
+    /// </summary>
+    public string? Format { get; init; }
+
+    /// <summary>
+    /// Provider filter for VEX exports.
+    /// </summary>
+    public IReadOnlyList<string>? Providers { get; init; }
+
+    /// <summary>
+    /// Output directory for the bundle files.
+    /// </summary>
+    public required string OutputDirectory { get; init; }
+
+    /// <summary>
+    /// Whether to include DSSE signatures.
+    /// </summary>
+    public bool IncludeSignatures { get; init; }
+
+    /// <summary>
+    /// Whether to include attestation metadata.
+    /// </summary>
+    public bool IncludeAttestations { get; init; }
+
+    /// <summary>
+    /// Tenant scope for the exports.
+    /// </summary>
+    public string? Tenant { get; init; }
+}
+
+/// <summary>
+/// Result model for mirror bundle creation.
+/// </summary>
+internal sealed record MirrorCreateResult
+{
+    /// <summary>
+    /// Path to the created bundle manifest.
+    /// </summary>
+    public required string ManifestPath { get; init; }
+
+    /// <summary>
+    /// Path to the bundle archive (if created).
+    /// </summary>
+    public string? BundlePath { get; init; }
+
+    /// <summary>
+    /// Path to the bundle signature (if created).
+    /// </summary>
+    public string? SignaturePath { get; init; }
+
+    /// <summary>
+    /// Number of exports included in the bundle.
+    /// </summary>
+    public int ExportCount { get; init; }
+
+    /// <summary>
+    /// Total size in bytes of all exported artifacts.
+    /// </summary>
+    public long TotalSizeBytes { get; init; }
+
+    /// <summary>
+    /// Bundle digest for verification.
+    /// </summary>
+    public string? BundleDigest { get; init; }
+
+    /// <summary>
+    /// Timestamp when the bundle was generated.
+    /// </summary>
+    public DateTimeOffset GeneratedAt { get; init; }
+
+    /// <summary>
+    /// Domain ID of the bundle.
+    /// </summary>
+    public required string DomainId { get; init; }
+
+    /// <summary>
+    /// Export details for verbose output.
+    /// </summary>
+    public IReadOnlyList<MirrorBundleExport>? Exports { get; init; }
+}