fix(retry): charge gate budget on any repeated failure fingerprint (#460)

gateFailureFingerprints held one slot per gate, so the budget only charged
when a failure repeated back to back. Whack-a-mole (fix A breaks B, fix B
breaks A) alternates two fingerprints forever, every round read as progress,
and the per-gate budget never triggered. Track the full set seen per gate and
charge when the current fingerprint is a repeat.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

core/kernel/src/main/kotlin/com/correx/core/kernel/orchestration/DefaultOrchestrationReducer.kt

@@ -83,7 +83,8 @@ class DefaultOrchestrationReducer : OrchestrationReducer {
             } else {
                 state.gateRetryBudgets
             },
-            gateFailureFingerprints = state.gateFailureFingerprints + (p.gate to p.fingerprint),
+            gateFailureFingerprints = state.gateFailureFingerprints +
+                (p.gate to ((state.gateFailureFingerprints[p.gate] ?: emptySet()) + p.fingerprint)),
         )
 
         is RetrySalvageDecidedEvent -> if (p.decision == SalvageDecision.CONTINUE) {

core/kernel/src/main/kotlin/com/correx/core/kernel/retry/DefaultRetryCoordinator.kt

@@ -26,9 +26,10 @@ class DefaultRetryCoordinator(
         policy: RetryPolicy,
     ): RetryDecision {
         val fingerprint = FailureFingerprint.of(failureReason)
-        val prevFingerprint = state.gateFailureFingerprints[gate]
-        val progressed = prevFingerprint != fingerprint
-        val charged = !progressed
+        // Charge when this failure has been seen before for this gate — a repeat means the round
+        // trip produced no state the gate has not already rejected. Comparing against only the
+        // previous fingerprint misses cycles: A/B/A alternation reads as progress forever.
+        val charged = fingerprint in (state.gateFailureFingerprints[gate] ?: emptySet())
         val currentCount = state.gateRetryBudgets[gate] ?: 0
         val newCount = if (charged) currentCount + 1 else currentCount
         val maxAttempts = policy.maxAttemptsFor(gate)