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src/Scanner/StellaOps.Scanner.Worker/Determinism/DeterminismContext.cs

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+using System;
+
+namespace StellaOps.Scanner.Worker.Determinism;
+
+/// <summary>
+/// Captures determinism-related toggles for the worker runtime.
+/// </summary>
+public sealed class DeterminismContext
+{
+    public DeterminismContext(bool fixedClock, DateTimeOffset fixedInstantUtc, int? rngSeed, bool filterLogs)
+    {
+        FixedClock = fixedClock;
+        FixedInstantUtc = fixedInstantUtc.ToUniversalTime();
+        RngSeed = rngSeed;
+        FilterLogs = filterLogs;
+    }
+
+    public bool FixedClock { get; }
+
+    public DateTimeOffset FixedInstantUtc { get; }
+
+    public int? RngSeed { get; }
+
+    public bool FilterLogs { get; }
+}

src/Scanner/StellaOps.Scanner.Worker/Determinism/DeterministicRandomProvider.cs

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+using System;
+
+namespace StellaOps.Scanner.Worker.Determinism;
+
+public interface IDeterministicRandomProvider
+{
+    Random Create();
+}
+
+/// <summary>
+/// Provides seeded <see cref="Random"/> instances when a seed is configured, otherwise defaults to a thread-safe system random.
+/// </summary>
+public sealed class DeterministicRandomProvider : IDeterministicRandomProvider
+{
+    private readonly int? _seed;
+
+    public DeterministicRandomProvider(int? seed)
+    {
+        _seed = seed;
+    }
+
+    public Random Create()
+    {
+        return _seed.HasValue ? new Random(_seed.Value) : Random.Shared;
+    }
+}

src/Scanner/StellaOps.Scanner.Worker/Determinism/DeterministicTimeProvider.cs

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+using System;
+
+namespace StellaOps.Scanner.Worker.Determinism;
+
+/// <summary>
+/// Time provider that always returns a fixed instant, used to enforce deterministic timestamps.
+/// </summary>
+public sealed class DeterministicTimeProvider : TimeProvider
+{
+    private readonly DateTimeOffset _fixedUtc;
+
+    public DeterministicTimeProvider(DateTimeOffset fixedUtc)
+    {
+        _fixedUtc = fixedUtc.ToUniversalTime();
+    }
+
+    public override DateTimeOffset GetUtcNow() => _fixedUtc;
+}