feat: add Attestation Chain and Triage Evidence API clients and models

- Implemented Attestation Chain API client with methods for verifying, fetching, and managing attestation chains.
- Created models for Attestation Chain, including DSSE envelope structures and verification results.
- Developed Triage Evidence API client for fetching finding evidence, including methods for evidence retrieval by CVE and component.
- Added models for Triage Evidence, encapsulating evidence responses, entry points, boundary proofs, and VEX evidence.
- Introduced mock implementations for both API clients to facilitate testing and development.

src/Scanner/__Libraries/StellaOps.Scanner.Emit/Native/NativeBinaryMetadata.cs

@@ -0,0 +1,55 @@
+namespace StellaOps.Scanner.Emit.Native;
+
+/// <summary>
+/// Metadata for a native binary component.
+/// </summary>
+public sealed record NativeBinaryMetadata
+{
+    /// <summary>Binary format (elf, pe, macho)</summary>
+    public required string Format { get; init; }
+
+    /// <summary>Build-ID with prefix (gnu-build-id:..., pe-cv:..., macho-uuid:...)</summary>
+    public string? BuildId { get; init; }
+
+    /// <summary>CPU architecture (x86_64, aarch64, arm, i686, etc.)</summary>
+    public string? Architecture { get; init; }
+
+    /// <summary>Whether this is a 64-bit binary</summary>
+    public bool Is64Bit { get; init; }
+
+    /// <summary>Operating system or platform</summary>
+    public string? Platform { get; init; }
+
+    /// <summary>File path within the container layer</summary>
+    public required string FilePath { get; init; }
+
+    /// <summary>SHA-256 digest of the file</summary>
+    public string? FileDigest { get; init; }
+
+    /// <summary>File size in bytes</summary>
+    public long FileSize { get; init; }
+
+    /// <summary>Container layer digest where this binary was introduced</summary>
+    public string? LayerDigest { get; init; }
+
+    /// <summary>Layer index (0-based)</summary>
+    public int LayerIndex { get; init; }
+
+    /// <summary>Product version from PE version resource</summary>
+    public string? ProductVersion { get; init; }
+
+    /// <summary>File version from PE version resource</summary>
+    public string? FileVersion { get; init; }
+
+    /// <summary>Company name from PE version resource</summary>
+    public string? CompanyName { get; init; }
+
+    /// <summary>Hardening flags (PIE, RELRO, NX, etc.)</summary>
+    public IReadOnlyDictionary<string, string>? HardeningFlags { get; init; }
+
+    /// <summary>Whether the binary is signed</summary>
+    public bool IsSigned { get; init; }
+
+    /// <summary>Signature details (Authenticode, codesign, etc.)</summary>
+    public string? SignatureDetails { get; init; }
+}