fix: correct SearchRequest field names (offset/limit, sortField/sortDir)

Dashboard was sending page/size but backend expects offset/limit.
Schema also had sort/order instead of sortField/sortDir.

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

ui/src/api/schema.d.ts

@@ -115,10 +115,10 @@ export interface components {
       agentId?: string;
       status?: string;
       text?: string;
-      page?: number;
-      size?: number;
-      sort?: string;
-      order?: string;
+      offset?: number;
+      limit?: number;
+      sortField?: string;
+      sortDir?: string;
     };
     ExecutionDetail: {
       executionId: string;