feat: exchange-level log viewer on ExchangeDetail page

Index exchangeId from Camel MDC (camel.exchangeId) as a top-level
keyword field in OpenSearch log indices. Add exchangeId filter to
the log query API and frontend hook. Show a LogViewer on the
ExchangeDetail page filtered to that exchange's logs, with search
input and level filter pills.

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

cameleer3-server-app/src/main/java/com/cameleer3/server/app/controller/LogQueryController.java

@@ -32,6 +32,7 @@ public class LogQueryController {
             @RequestParam(required = false) String agentId,
             @RequestParam(required = false) String level,
             @RequestParam(required = false) String query,
+            @RequestParam(required = false) String exchangeId,
             @RequestParam(required = false) String from,
             @RequestParam(required = false) String to,
             @RequestParam(defaultValue = "200") int limit) {
@@ -42,7 +43,7 @@ public class LogQueryController {
         Instant toInstant = to != null ? Instant.parse(to) : null;
 
         List<LogEntryResponse> entries = logIndex.search(
-                application, agentId, level, query, fromInstant, toInstant, limit);
+                application, agentId, level, query, exchangeId, fromInstant, toInstant, limit);
 
         return ResponseEntity.ok(entries);
     }