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

docs/plans/2026-11-09-out-of-process-script-runner-design.md

@@ -677,6 +677,15 @@ per-shard state, restarts in the last hour and the quarantine list. Quarantines
      publish + the low-privilege account / pipe ACL / firewall rule (installer), the runner-state gauge and readiness
      component, victim re-evaluation on shard return, isolation-worker idle stop, the orphan sweep by nonce file, the
      scripted-alarm seam, the docker-dev enablement and the §8 perf harness.
+   - **Second P1 slice (lmxopcua#780):** the HMAC'd PE cache (§7; keyed by source + kind + a compile fingerprint, tampered
+     or mismatched entries evicted, pruned by recency at startup instead of by generation — this runner has no
+     generation object), attribution before release (the quarantine race), loading keys counted in attribution
+     (culprit-finding for a compile that crashes its worker, by isolation rather than the §5.3.5 three-strikes
+     bisection — loads are per key here), proactive restart + `Recovery` / `RetryWhen` re-evaluation of victims in the
+     VT and Calc seams, isolation idle stop (`IsolationIdleTimeout`), the crash-loop circuit (`CircuitOpenAfter`), the
+     §10 gauges and histograms, the degraded-but-ready `script-runner` health check (§14 #12), and the orphan sweep by
+     launch marker (pid + start time + image, host gone). Still open: self-contained worker publish, installer (account,
+     pipe ACL, firewall), docker-dev live drill, scripted-alarm seam, the §4.5 batch submit, the §8 perf harness.
 3. **P2, shadow mode on docker-dev and QA.**
    - `Shadow` runs the **in-process** evaluation as the published result, and *also* submits to the worker.
    - It compares value, status class and failure kind per evaluation, and counts