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

src/Core/ZB.MOM.WW.OtOpcUa.Core.Scripting/IScriptRunner.cs

@@ -97,6 +97,13 @@ public sealed record ScriptRunOutcome(ScriptRunStatus Status, object? Value, str
     /// <summary>Reason when no worker became ready within <see cref="ScriptWorkerOptions.UnavailableGrace"/>.</summary>
     public const string RunnerUnavailableReason = "script runner unavailable";
 
+    /// <summary>
+    ///     For <see cref="ScriptRunStatus.Unavailable"/>: completes when the runner can run this script again (its worker
+    ///     is back), so the seam re-evaluates it then with its latest inputs (design §9, "re-evaluated on the shard's
+    ///     return"). Null when there is nothing to wait for.
+    /// </summary>
+    public Task? Recovery { get; init; }
+
     /// <summary>A successful run.</summary>
     /// <param name="value">The script's result.</param>
     /// <returns>The outcome.</returns>
@@ -130,7 +137,7 @@ public static class ScriptRunOutcomeExtensions
         {
             ScriptRunStatus.Ok => Commons.Engines.VirtualTagEvalResult.Ok(outcome.Value),
             ScriptRunStatus.Unavailable => Commons.Engines.VirtualTagEvalResult.Unavailable(
-                outcome.Reason ?? ScriptRunOutcome.RunnerUnavailableReason),
+                outcome.Reason ?? ScriptRunOutcome.RunnerUnavailableReason) with { RetryWhen = outcome.Recovery },
             _ => Commons.Engines.VirtualTagEvalResult.Failure(outcome.Reason ?? "evaluator failure"),
         };
     }