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/test/java/com/cameleer3/server/app/storage/PostgresStatsStoreIT.java

@@ -54,10 +54,10 @@ class PostgresStatsStoreIT extends AbstractPostgresIT {
         assertFalse(ts.buckets().isEmpty());
     }
 
-    private void insertExecution(String id, String routeId, String groupName,
+    private void insertExecution(String id, String routeId, String applicationName,
                                   String status, Instant startTime, long durationMs) {
         executionStore.upsert(new ExecutionRecord(
-                id, routeId, "agent-1", groupName, status, null, null,
+                id, routeId, "agent-1", applicationName, status, null, null,
                 startTime, startTime.plusMillis(durationMs), durationMs,
                 status.equals("FAILED") ? "error" : null, null, null));
     }