refactor: rename group/groupName to application/applicationName

The execution-related "group" concept actually represents the
application name. Rename all Java fields, API parameters, and frontend
types from groupName→applicationName and group→application for clarity.

- Java records: ExecutionSummary, ExecutionDetail, ExecutionDocument,
  ExecutionRecord, ProcessorRecord
- API params: SearchRequest.group→application, SearchController
  @RequestParam group→application
- Services: IngestionService, DetailService, SearchIndexer, StatsStore
- Frontend: schema.d.ts, Dashboard, ExchangeDetail, RouteDetail,
  executions query hooks

Database column names (group_name) and OpenSearch field names are
unchanged — only the API-facing Java/TS field names are renamed.

RBAC group references (groups table, GroupRepository, GroupsTab) are
a separate domain concept and are NOT affected by this change.

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

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

@@ -288,7 +288,7 @@ public class OpenSearchIndex implements SearchIndex {
         map.put("execution_id", doc.executionId());
         map.put("route_id", doc.routeId());
         map.put("agent_id", doc.agentId());
-        map.put("group_name", doc.groupName());
+        map.put("group_name", doc.applicationName());
         map.put("status", doc.status());
         map.put("correlation_id", doc.correlationId());
         map.put("exchange_id", doc.exchangeId());