feat(scripting): PE cache, quarantine-race fix, recovery, readiness for the out-of-process runner (lmxopcua#780 P1)

Second P1 slice of docs/plans/2026-11-09-out-of-process-script-runner-design.md; still opt-in behind
Scripting:Runner=OutOfProcess (InProcess unchanged).

- Compiled-PE cache (design §7, §14 #8): Scripting:Worker:PeCacheDir holds <dir>/pe/<id>.pe entries authenticated
  with HMAC-SHA256 under a per-node random key (<dir>/pe-cache.key, created by the host, 0600/0700 on Unix), handed to
  the worker in Hello. Entry id = SHA-256(compile fingerprint + kind + source); the fingerprint covers the Roslyn
  version, the Core.Scripting build (analyzer, wrapper, stack guard), the sandbox reference set and the runtime. Edited,
  truncated, other-key or renamed entries are rejected, deleted and recompiled; the worker never loads unverified bytes.
  Pruned by recency at startup (30 d / 50 000). ScriptEvaluator splits into CompileToImage + FromImage. Measured on
  40 scripts, restart to every first result: macOS 820 ms no cache / 840 ms empty / 85 ms warm;
  windev (Windows) 9.5 s / 9.4 s / 1.0 s.
- Quarantine race: WorkerConnection runs exit attribution synchronously BEFORE completing the evaluations/loads it held
  (and before Exited), and the shard passes it straight to the runner — a kill strike is in place before the killed
  key's slot is released.
- Supervision: a dead worker restarts by itself after its backoff; Unavailable outcomes carry ScriptRunOutcome.Recovery
  (-> VirtualTagEvalResult.RetryWhen) and the VT actor / Calculation driver re-evaluate once against current inputs when
  it completes. Isolation worker stops after Scripting:Worker:IsolationIdleTimeout (10 min). Keys compiling when a
  worker dies are suspects too (isolation finds a poison compile and quarantines it). Startup orphan sweep by launch
  marker: kills only a process whose marker's host is gone and whose pid + start time + image match.
- Crash-loop circuit (Scripting:Worker:CircuitOpenAfter, 2 min): runner Unavailable, one Error, evaluations answered
  at once while shards keep retrying at the cap.
- Observability (§10): otopcua.script.runner.state, worker.up/inflight/queue_depth/heap_bytes (shard),
  ipc.roundtrip + eval.duration (kind), compile{cache}, isolation.suspects, exits reason=idle. `script-runner` health
  check on the ready tier, at worst Degraded (§14 #12: degraded but still ready).

Left on #780: self-contained worker publish, installer (account, pipe ACL, firewall), docker-dev live drill,
scripted-alarm seam, the §4.5 per-seam batch submit, the §8 perf harness.

Tests: SupervisionTests, PeCacheStoreTests/PeCacheWorkerTests (real workers), ScriptRunnerHealthCheckTests, VT + Calc
recovery seam tests; 14 mutations each turned their test red.

Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV

tests/Server/ZB.MOM.WW.OtOpcUa.ScriptWorker.Tests/TestSupport.cs

@@ -37,7 +37,8 @@ internal static class Scripts
 
     /// <summary>Options for a single-shard runner with short budgets, so the containment tests run in seconds.</summary>
     public static ScriptingOptions Options(int shards = 1, TimeSpan? hardGrace = null, int quarantineAfterKills = 2,
-        int probation = 20, TimeSpan? unavailableGrace = null, string? workerPath = null, long heapLimit = 256L * 1024 * 1024)
+        int probation = 20, TimeSpan? unavailableGrace = null, string? workerPath = null, long heapLimit = 256L * 1024 * 1024,
+        string? peCacheDir = null, TimeSpan? isolationIdle = null, TimeSpan? circuitOpenAfter = null)
         => new()
         {
             Runner = ScriptRunnerMode.OutOfProcess,
@@ -51,12 +52,34 @@ internal static class Scripts
                 UnavailableGrace = unavailableGrace ?? TimeSpan.FromSeconds(30),
                 ExecutablePath = workerPath,
                 HeapLimitBytes = heapLimit,
+                PeCacheDir = peCacheDir,
+                IsolationIdleTimeout = isolationIdle ?? ScriptWorkerOptions.DefaultIsolationIdleTimeout,
+                CircuitOpenAfter = circuitOpenAfter ?? ScriptWorkerOptions.DefaultCircuitOpenAfter,
             },
         };
 
-    public static OutOfProcessScriptRunner Runner(ScriptingOptions options, ILogger? log = null)
+    /// <summary>A fresh, empty temp directory, deleted by <see cref="IDisposable.Dispose"/>.</summary>
+    public sealed class TempDir : IDisposable
+    {
+        public TempDir()
+        {
+            Path = System.IO.Path.Combine(System.IO.Path.GetTempPath(), "otopcua-sw-test-" + Guid.NewGuid().ToString("N")[..12]);
+            Directory.CreateDirectory(Path);
+        }
+
+        public string Path { get; }
+
+        public void Dispose()
+        {
+            try { Directory.Delete(Path, recursive: true); } catch { /* best effort */ }
+        }
+    }
+
+    public static OutOfProcessScriptRunner Runner(ScriptingOptions options, ILogger? log = null,
+        TimeSpan? maintenanceInterval = null, string? markerDirectory = null)
         => new(options, log ?? new LoggerConfiguration().CreateLogger(), null,
-            heartbeatInterval: TimeSpan.FromSeconds(1), loadTimeout: TimeSpan.FromSeconds(60));
+            heartbeatInterval: TimeSpan.FromSeconds(1), loadTimeout: TimeSpan.FromSeconds(60),
+            maintenanceInterval: maintenanceInterval, markerDirectory: markerDirectory);
 
     public static async Task<T> Eventually<T>(Func<T?> probe, TimeSpan timeout, string what) where T : class
     {