feat(session): add optional end-of-session summarization

src/session/index.ts

@@ -4,3 +4,4 @@ export { SessionIndexer, tokenize } from './indexer.js';
 export type { HistoryMetadata, HistoryIndexerConfig } from './indexer.js';
 export { SessionSearch } from './search.js';
 export type { HistorySearchResult, HistorySearchConfig } from './search.js';
+export { summarizeSessionOnEnd, sessionEndSummaryInternals, type SessionEndSummaryConfig, type SessionEndSummaryResult } from './endSummary.js';