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>

ui/src/pages/ExchangeDetail/ExchangeDetail.tsx

@@ -94,7 +94,7 @@ export default function ExchangeDetail() {
     <div>
       <Breadcrumb items={[
         { label: 'Dashboard', href: '/apps' },
-        { label: detail.groupName || 'App', href: `/apps/${detail.groupName}` },
+        { label: detail.applicationName || 'App', href: `/apps/${detail.applicationName}` },
         { label: id?.slice(0, 12) || '' },
       ]} />
 
@@ -109,11 +109,11 @@ export default function ExchangeDetail() {
                 <Badge label={detail.status} color={detail.status === 'COMPLETED' ? 'success' : 'error'} variant="filled" />
               </div>
               <div className={styles.exchangeRoute}>
-                Route: <span className={styles.routeLink} onClick={() => navigate(`/apps/${detail.groupName}/${detail.routeId}`)}>{detail.routeId}</span>
-                {detail.groupName && (
+                Route: <span className={styles.routeLink} onClick={() => navigate(`/apps/${detail.applicationName}/${detail.routeId}`)}>{detail.routeId}</span>
+                {detail.applicationName && (
                   <>
                     <span className={styles.headerDivider}>&middot;</span>
-                    App: <MonoText size="xs">{detail.groupName}</MonoText>
+                    App: <MonoText size="xs">{detail.applicationName}</MonoText>
                   </>
                 )}
               </div>