Add property-based tests for SBOM/VEX document ordering and Unicode normalization determinism

- Implement `SbomVexOrderingDeterminismProperties` for testing component list and vulnerability metadata hash consistency.
- Create `UnicodeNormalizationDeterminismProperties` to validate NFC normalization and Unicode string handling.
- Add project file for `StellaOps.Testing.Determinism.Properties` with necessary dependencies.
- Introduce CI/CD template validation tests including YAML syntax checks and documentation content verification.
- Create validation script for CI/CD templates ensuring all required files and structures are present.

src/AdvisoryAI/StellaOps.AdvisoryAI/Explanation/ExplanationResult.cs

@@ -0,0 +1,142 @@
+namespace StellaOps.AdvisoryAI.Explanation;
+
+/// <summary>
+/// Citation linking an explanation claim to evidence.
+/// </summary>
+public sealed record ExplanationCitation
+{
+    /// <summary>
+    /// Claim text from the explanation.
+    /// </summary>
+    public required string ClaimText { get; init; }
+
+    /// <summary>
+    /// Evidence node ID supporting this claim.
+    /// </summary>
+    public required string EvidenceId { get; init; }
+
+    /// <summary>
+    /// Type of evidence (sbom, reachability, runtime, vex, patch).
+    /// </summary>
+    public required string EvidenceType { get; init; }
+
+    /// <summary>
+    /// Whether the citation was verified against the evidence.
+    /// </summary>
+    public required bool Verified { get; init; }
+
+    /// <summary>
+    /// Excerpt from the evidence supporting the claim.
+    /// </summary>
+    public string? EvidenceExcerpt { get; init; }
+}
+
+/// <summary>
+/// Authority level of the explanation.
+/// </summary>
+public enum ExplanationAuthority
+{
+    /// <summary>
+    /// All claims are evidence-backed (≥80% citation rate, all verified).
+    /// </summary>
+    EvidenceBacked,
+
+    /// <summary>
+    /// AI suggestion requiring human review.
+    /// </summary>
+    Suggestion
+}
+
+/// <summary>
+/// Result of explanation generation.
+/// Sprint: SPRINT_20251226_015_AI_zastava_companion
+/// Task: ZASTAVA-07
+/// </summary>
+public sealed record ExplanationResult
+{
+    /// <summary>
+    /// Unique ID for this explanation.
+    /// </summary>
+    public required string ExplanationId { get; init; }
+
+    /// <summary>
+    /// The explanation content (markdown supported).
+    /// </summary>
+    public required string Content { get; init; }
+
+    /// <summary>
+    /// 3-line summary for compact display.
+    /// </summary>
+    public required ExplanationSummary Summary { get; init; }
+
+    /// <summary>
+    /// Citations linking claims to evidence.
+    /// </summary>
+    public required IReadOnlyList<ExplanationCitation> Citations { get; init; }
+
+    /// <summary>
+    /// Overall confidence score (0.0-1.0).
+    /// </summary>
+    public required double ConfidenceScore { get; init; }
+
+    /// <summary>
+    /// Citation rate (verified citations / total claims).
+    /// </summary>
+    public required double CitationRate { get; init; }
+
+    /// <summary>
+    /// Authority classification.
+    /// </summary>
+    public required ExplanationAuthority Authority { get; init; }
+
+    /// <summary>
+    /// Evidence node IDs used in this explanation.
+    /// </summary>
+    public required IReadOnlyList<string> EvidenceRefs { get; init; }
+
+    /// <summary>
+    /// Model ID used for generation.
+    /// </summary>
+    public required string ModelId { get; init; }
+
+    /// <summary>
+    /// Prompt template version.
+    /// </summary>
+    public required string PromptTemplateVersion { get; init; }
+
+    /// <summary>
+    /// Input hashes for replay.
+    /// </summary>
+    public required IReadOnlyList<string> InputHashes { get; init; }
+
+    /// <summary>
+    /// Generation timestamp (UTC ISO-8601).
+    /// </summary>
+    public required string GeneratedAt { get; init; }
+
+    /// <summary>
+    /// Output hash for verification.
+    /// </summary>
+    public required string OutputHash { get; init; }
+}
+
+/// <summary>
+/// 3-line summary following the AI UX pattern.
+/// </summary>
+public sealed record ExplanationSummary
+{
+    /// <summary>
+    /// Line 1: What changed/what is it.
+    /// </summary>
+    public required string Line1 { get; init; }
+
+    /// <summary>
+    /// Line 2: Why it matters.
+    /// </summary>
+    public required string Line2 { get; init; }
+
+    /// <summary>
+    /// Line 3: Next action.
+    /// </summary>
+    public required string Line3 { get; init; }
+}