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/api/schema.d.ts

@@ -1079,7 +1079,7 @@ export interface components {
             routeId?: string;
             agentId?: string;
             processorType?: string;
-            group?: string;
+            application?: string;
             agentIds?: string[];
             /** Format: int32 */
             offset?: number;
@@ -1092,7 +1092,7 @@ export interface components {
             executionId: string;
             routeId: string;
             agentId: string;
-            groupName: string;
+            applicationName: string;
             status: string;
             /** Format: date-time */
             startTime: string;
@@ -1327,7 +1327,7 @@ export interface components {
             errorStackTrace: string;
             diagramContentHash: string;
             processors: components["schemas"]["ProcessorNode"][];
-            groupName?: string;
+            applicationName?: string;
             children?: components["schemas"]["ProcessorNode"][];
         };
         ProcessorNode: {
@@ -2977,7 +2977,7 @@ export interface operations {
                 from: string;
                 to?: string;
                 routeId?: string;
-                group?: string;
+                application?: string;
             };
             header?: never;
             path?: never;
@@ -3003,7 +3003,7 @@ export interface operations {
                 to?: string;
                 buckets?: number;
                 routeId?: string;
-                group?: string;
+                application?: string;
             };
             header?: never;
             path?: never;