fix(scripting): only timeouts are quarantine strikes; alarm Bad annotation once per bucket change (fix round 1 I1, I3)

- I1 ScriptRunGuard: a run refused because the previous one is still
  executing is a Bad publish plus otopcua.script.run_refused, and no longer
  a quarantine strike. Only a timeout (and an allocation breach) counts;
  a refusal neither adds to nor resets the timeout streak; a completed run
  (value or throw) resets it. On a 1 Hz trigger with a 2 s budget a single
  4 s overrun is one timeout plus two refusals and must not quarantine.
  Tests updated across the guard, the alarm engine, the Calculation
  evaluator and the VT evaluator, plus
  Refusals_neither_count_toward_nor_reset_the_timeout_streak.
- I3 ScriptedAlarmEngine: the quality bucket is tracked only after the
  predicate completes (or in the inputs-not-ready path), so the tracked
  bucket is the last one annotated. A refused or quarantined predicate
  used to re-track the input bucket Good before the attempt and then flip
  it Bad, emitting QualityChanged on every push. The run-guard tests now
  count emissions (exactly 1 across N pushes, refused and quarantined
  cases), with a healthy sibling's dispatch count as the positive control
  that every push was processed. Both were red before the fix.

Refs #734

Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT

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

@@ -24,8 +24,10 @@ namespace ZB.MOM.WW.OtOpcUa.Core.Scripting;
 ///         <see cref="ScriptRunRefusedException"/> (<see cref="PreviousRunStillRunningReason"/>), counted on
 ///         <see cref="RefusedWhileRunningCount"/>. One orphan per script, never one per trigger.</item>
 ///         <item><b>Quarantines after <see cref="ScriptingOptions.QuarantineAfterConsecutiveTimeouts"/>
-///         consecutive non-completions</b> (timeouts and still-running refusals both count; a run that
-///         returns — a value or a throw — resets the count): no further dispatch, every attempt throws
+///         consecutive timeouts</b> (only a timeout is a strike; a refusal is a Bad publish plus its counter
+///         and leaves the streak untouched — on a 1 Hz trigger with a 2 s budget one 4 s overrun is a
+///         timeout plus two refusals and must not quarantine; a run that returns — a value or a throw —
+///         resets the streak): no further dispatch, every attempt throws
 ///         <see cref="ScriptQuarantinedException"/>, one Error log, one <c>otopcua.script.quarantined</c>
 ///         increment, one <see cref="Quarantined"/> event. Lifted by a source change (the operator fixed the
 ///         script — a new source identity under the same key starts clean and the old orphan no longer blocks
@@ -177,10 +179,12 @@ public sealed class ScriptRunGuard
         // not) still holds the slot is refused here, before anything is dispatched to the pool.
         if (Interlocked.CompareExchange(ref state.InFlight, 1, 0) != 0)
         {
+            // A refusal is a Bad publish plus its counter — NOT a strike. Only a timeout (and an allocation
+            // breach) counts toward quarantine: on a 1 Hz trigger with a 2 s budget a single 4 s overrun is
+            // one timeout followed by two refusals, and counting those would quarantine a script that merely
+            // ran long once. The refusal also leaves the timeout streak untouched.
             Interlocked.Increment(ref _refused);
             RefusedCounter.Add(1, new KeyValuePair<string, object?>("script", key));
-            if (NoteNonCompletion(key, state, "refused: previous evaluation still running"))
-                throw new ScriptQuarantinedException(key, state.QuarantineReason!);
             throw new ScriptRunRefusedException(key);
         }
 
@@ -241,7 +245,7 @@ public sealed class ScriptRunGuard
             // The caller's cancel wins even when it lands a few µs after the timeout fired.
             if (ct.IsCancellationRequested) throw new OperationCanceledException(ct);
             runCts.Cancel();
-            if (NoteNonCompletion(key, state, $"timed out after {timeout.TotalMilliseconds:F1} ms"))
+            if (NoteTimeout(key, state, timeout))
                 throw new ScriptQuarantinedException(key, state.QuarantineReason!);
             throw new ScriptTimeoutException(timeout);
         }
@@ -252,11 +256,11 @@ public sealed class ScriptRunGuard
         catch (Exception)
         {
             // The script returned control (by throwing) — that is a completion for quarantine purposes.
-            Interlocked.Exchange(ref state.ConsecutiveNonCompletions, 0);
+            Interlocked.Exchange(ref state.ConsecutiveTimeouts, 0);
             throw;
         }
 
-        Interlocked.Exchange(ref state.ConsecutiveNonCompletions, 0);
+        Interlocked.Exchange(ref state.ConsecutiveTimeouts, 0);
         if (BreachedBudget(slot.AllocatedBytes))
         {
             // The continuation above has already (or will have) quarantined the key; make the reason visible
@@ -291,13 +295,14 @@ public sealed class ScriptRunGuard
         }
     }
 
-    /// <summary>Record a non-completion; returns true when it tipped the key into quarantine.</summary>
-    private bool NoteNonCompletion(string key, KeyState state, string what)
+    /// <summary>Record a timeout strike; returns true when it tipped the key into quarantine. A completed run
+    /// (value or throw) resets the streak; a refusal neither counts nor resets.</summary>
+    private bool NoteTimeout(string key, KeyState state, TimeSpan timeout)
     {
-        var count = Interlocked.Increment(ref state.ConsecutiveNonCompletions);
+        var count = Interlocked.Increment(ref state.ConsecutiveTimeouts);
         if (count < _quarantineThreshold) return false;
         Quarantine(key, state,
-            $"{count} consecutive evaluation(s) did not complete (last: {what}); " +
+            $"{count} consecutive evaluation(s) timed out (budget {timeout.TotalMilliseconds:F0} ms); " +
             "the script is not evaluated again until its source changes or it is redeployed",
             "timeouts");
         return true;
@@ -333,7 +338,7 @@ public sealed class ScriptRunGuard
     {
         public string? SourceIdentity = sourceIdentity;
         public int InFlight;
-        public int ConsecutiveNonCompletions;
+        public int ConsecutiveTimeouts;
         public string? QuarantineReason;
     }
 
@@ -368,7 +373,7 @@ public sealed class ScriptRunRefusedException : Exception
 
 /// <summary>
 ///     Thrown by <see cref="ScriptRunGuard.RunAsync{TContext, TResult}"/> for a quarantined script: repeated
-///     non-completion or an allocation-budget breach. Nothing is dispatched while quarantined; the seam
+///     timeouts or an allocation-budget breach. Nothing is dispatched while quarantined; the seam
 ///     publishes Bad carrying the reason, which an operator clears by fixing the script (source change) or
 ///     redeploying.
 /// </summary>

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

@@ -33,10 +33,11 @@ public sealed class ScriptingOptions
     public long MaxAllocBytesPerRun { get; set; } = DefaultMaxAllocBytesPerRun;
 
     /// <summary>
-    ///     Consecutive non-completions (a run that times out, or a run refused because the previous one is
-    ///     still executing) after which the script is quarantined: no further runs are dispatched, every
+    ///     Consecutive timeouts after which the script is quarantined: no further runs are dispatched, every
     ///     evaluation reports Bad, and the quarantine lifts only on a source change, a redeploy or an explicit
-    ///     reset. Default 3; values below 1 are treated as 1.
+    ///     reset. Only a timeout is a strike — a run refused because the previous one is still executing is
+    ///     reported Bad and counted, but neither adds to nor resets the streak; a completed run (value or
+    ///     throw) resets it. Default 3; values below 1 are treated as 1.
     /// </summary>
     public int QuarantineAfterConsecutiveTimeouts { get; set; } = DefaultQuarantineAfterConsecutiveTimeouts;
 }