Refactor code structure for improved readability and maintainability; optimize performance in key functions.

src/Policy/__Libraries/StellaOps.Policy/Gates/PolicyGateAbstractions.cs

@@ -0,0 +1,53 @@
+using System.Collections.Immutable;
+using StellaOps.Policy.TrustLattice;
+
+namespace StellaOps.Policy.Gates;
+
+public sealed record PolicyGateContext
+{
+    public string Environment { get; init; } = "production";
+    public int UnknownCount { get; init; }
+    public IReadOnlyList<double> UnknownClaimScores { get; init; } = Array.Empty<double>();
+    public IReadOnlyDictionary<string, double> SourceInfluence { get; init; } = new Dictionary<string, double>(StringComparer.Ordinal);
+    public bool HasReachabilityProof { get; init; }
+    public string? Severity { get; init; }
+    public IReadOnlyCollection<string> ReasonCodes { get; init; } = Array.Empty<string>();
+}
+
+public sealed record GateResult
+{
+    public required string GateName { get; init; }
+    public required bool Passed { get; init; }
+    public required string? Reason { get; init; }
+    public required ImmutableDictionary<string, object> Details { get; init; }
+}
+
+public sealed record GateEvaluationResult
+{
+    public required bool AllPassed { get; init; }
+    public required ImmutableArray<GateResult> Results { get; init; }
+    public GateResult? FirstFailure => Results.FirstOrDefault(r => !r.Passed);
+}
+
+public interface IPolicyGate
+{
+    Task<GateResult> EvaluateAsync(
+        MergeResult mergeResult,
+        PolicyGateContext context,
+        CancellationToken ct = default);
+}
+
+public sealed record PolicyGateRegistryOptions
+{
+    public bool StopOnFirstFailure { get; init; } = true;
+}
+
+public interface IPolicyGateRegistry
+{
+    void Register<TGate>(string name) where TGate : IPolicyGate;
+
+    Task<GateEvaluationResult> EvaluateAsync(
+        MergeResult mergeResult,
+        PolicyGateContext context,
+        CancellationToken ct = default);
+}