fix: use .keyword suffix on both exchangeId term queries

Defensive: use .keyword on the top-level exchangeId field too, in
case indices were created before the explicit keyword mapping was
added to the template.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-app/src/main/java/com/cameleer3/server/app/search/OpenSearchLogIndex.java

@@ -112,7 +112,7 @@ public class OpenSearchLogIndex {
             if (exchangeId != null && !exchangeId.isEmpty()) {
                 // Match on top-level field (new records) or MDC nested field (old records)
                 bool.must(Query.of(q -> q.bool(b -> b
-                        .should(Query.of(s -> s.term(t -> t.field("exchangeId").value(FieldValue.of(exchangeId)))))
+                        .should(Query.of(s -> s.term(t -> t.field("exchangeId.keyword").value(FieldValue.of(exchangeId)))))
                         .should(Query.of(s -> s.term(t -> t.field("mdc.camel.exchangeId.keyword").value(FieldValue.of(exchangeId)))))
                         .minimumShouldMatch("1"))));
             }