feat(metrics): Implement scan metrics repository and PostgreSQL integration

- Added IScanMetricsRepository interface for scan metrics persistence and retrieval.
- Implemented PostgresScanMetricsRepository for PostgreSQL database interactions, including methods for saving and retrieving scan metrics and execution phases.
- Introduced methods for obtaining TTE statistics and recent scans for tenants.
- Implemented deletion of old metrics for retention purposes.

test(tests): Add SCA Failure Catalogue tests for FC6-FC10

- Created ScaCatalogueDeterminismTests to validate determinism properties of SCA Failure Catalogue fixtures.
- Developed ScaFailureCatalogueTests to ensure correct handling of specific failure modes in the scanner.
- Included tests for manifest validation, file existence, and expected findings across multiple failure cases.

feat(telemetry): Integrate scan completion metrics into the pipeline

- Introduced IScanCompletionMetricsIntegration interface and ScanCompletionMetricsIntegration class to record metrics upon scan completion.
- Implemented proof coverage and TTE metrics recording with logging for scan completion summaries.

src/Policy/__Libraries/StellaOps.Policy/Scoring/FreshnessAwareScoringService.cs

@@ -0,0 +1,129 @@
+// -----------------------------------------------------------------------------
+// FreshnessAwareScoringService.cs
+// Sprint: SPRINT_3401_0001_0001_determinism_scoring_foundations
+// Task: DET-3401-003
+// Description: Integrates freshness multiplier into evidence scoring pipeline
+// -----------------------------------------------------------------------------
+
+using Microsoft.Extensions.Logging;
+
+namespace StellaOps.Policy.Scoring;
+
+/// <summary>
+/// Integrates evidence freshness into the scoring pipeline.
+/// </summary>
+public interface IFreshnessAwareScoringService
+{
+    /// <summary>
+    /// Applies freshness adjustment to a finding's score.
+    /// </summary>
+    /// <param name="baseScore">Original score (0-100 or 0-10 depending on scale).</param>
+    /// <param name="evidenceTimestamp">When the evidence was collected.</param>
+    /// <param name="evaluationTime">Time of evaluation (for deterministic replay).</param>
+    /// <returns>Adjusted score with explanation.</returns>
+    FreshnessAdjustedScore AdjustForFreshness(
+        int baseScore,
+        DateTimeOffset evidenceTimestamp,
+        DateTimeOffset evaluationTime);
+
+    /// <summary>
+    /// Gets the freshness bucket for a given evidence age.
+    /// </summary>
+    FreshnessBucketResult GetFreshnessBucket(
+        DateTimeOffset evidenceTimestamp,
+        DateTimeOffset evaluationTime);
+}
+
+/// <summary>
+/// Result of freshness adjustment with explanation data.
+/// </summary>
+/// <param name="OriginalScore">The score before freshness adjustment.</param>
+/// <param name="AdjustedScore">The score after freshness adjustment.</param>
+/// <param name="MultiplierBps">The multiplier applied (basis points).</param>
+/// <param name="EvidenceAgeDays">Age of the evidence in days.</param>
+/// <param name="BucketName">Name of the freshness bucket.</param>
+public sealed record FreshnessAdjustedScore(
+    int OriginalScore,
+    int AdjustedScore,
+    int MultiplierBps,
+    int EvidenceAgeDays,
+    string BucketName);
+
+/// <summary>
+/// Result of freshness bucket lookup.
+/// </summary>
+/// <param name="AgeDays">Age of evidence in days.</param>
+/// <param name="BucketName">Human-readable bucket name.</param>
+/// <param name="MultiplierBps">Multiplier in basis points.</param>
+/// <param name="MultiplierPercent">Multiplier as percentage.</param>
+public sealed record FreshnessBucketResult(
+    int AgeDays,
+    string BucketName,
+    int MultiplierBps,
+    decimal MultiplierPercent);
+
+public sealed class FreshnessAwareScoringService : IFreshnessAwareScoringService
+{
+    private readonly EvidenceFreshnessCalculator _calculator;
+    private readonly ILogger<FreshnessAwareScoringService> _logger;
+
+    public FreshnessAwareScoringService(
+        FreshnessMultiplierConfig? config = null,
+        ILogger<FreshnessAwareScoringService>? logger = null)
+    {
+        _calculator = new EvidenceFreshnessCalculator(config);
+        _logger = logger ?? Microsoft.Extensions.Logging.Abstractions.NullLogger<FreshnessAwareScoringService>.Instance;
+    }
+
+    public FreshnessAdjustedScore AdjustForFreshness(
+        int baseScore,
+        DateTimeOffset evidenceTimestamp,
+        DateTimeOffset evaluationTime)
+    {
+        var ageDays = (int)(evaluationTime - evidenceTimestamp).TotalDays;
+        if (ageDays < 0) ageDays = 0;
+
+        var multiplierBps = _calculator.CalculateMultiplierBps(evidenceTimestamp, evaluationTime);
+        var adjustedScore = _calculator.ApplyFreshness(baseScore, evidenceTimestamp, evaluationTime);
+        var bucketName = GetBucketName(ageDays);
+
+        _logger.LogDebug(
+            "Freshness adjustment: base={BaseScore}, adjusted={AdjustedScore}, age={AgeDays}d, bucket={Bucket}, multiplier={Mult}bps",
+            baseScore, adjustedScore, ageDays, bucketName, multiplierBps);
+
+        return new FreshnessAdjustedScore(
+            OriginalScore: baseScore,
+            AdjustedScore: adjustedScore,
+            MultiplierBps: multiplierBps,
+            EvidenceAgeDays: ageDays,
+            BucketName: bucketName);
+    }
+
+    public FreshnessBucketResult GetFreshnessBucket(
+        DateTimeOffset evidenceTimestamp,
+        DateTimeOffset evaluationTime)
+    {
+        var ageDays = (int)(evaluationTime - evidenceTimestamp).TotalDays;
+        if (ageDays < 0) ageDays = 0;
+
+        var multiplierBps = _calculator.CalculateMultiplierBps(evidenceTimestamp, evaluationTime);
+        var bucketName = GetBucketName(ageDays);
+        var multiplierPercent = multiplierBps / 100m;
+
+        return new FreshnessBucketResult(
+            AgeDays: ageDays,
+            BucketName: bucketName,
+            MultiplierBps: multiplierBps,
+            MultiplierPercent: multiplierPercent);
+    }
+
+    private static string GetBucketName(int ageDays) => ageDays switch
+    {
+        <= 7 => "fresh_7d",
+        <= 30 => "recent_30d",
+        <= 90 => "moderate_90d",
+        <= 180 => "aging_180d",
+        <= 365 => "stale_365d",
+        _ => "ancient"
+    };
+}