feat: verify end-to-end lazy graph expansion - Task 5 complete

All lazy graph expansion requirements verified:
- Lazy on-demand graph expansion with hub stations
- BFS/Dijkstra with depth limiting (4-5 transfers max)
- On-demand /search requests for relevant station pairs
- Aggressive caching with TTL policies
- Transfer limit enforcement
- MCT calculation during lazy expansion

docs/plans/2026-08-14-lazy-graph-expansion.md

@@ -65,19 +65,19 @@ Implement lazy (on-demand) graph expansion for trip routing within Yandex.Schedu
 - [x] Run tests - must pass before task 4
 
 ### Task 4: Implement cache-aware search results with TTL policies
-- [ ] Integrate search result caching using existing cache TTL policies (near-term: 2-6h, far-term: 7d)
-- [ ] Add cache lookup before on-demand /search calls
-- [ ] Write tests for cache hit/miss with lazy expansion
-- [ ] Write tests for TTL policy selection based on date distance
-- [ ] Run tests - must pass before task 5
+- [x] Integrate search result caching using existing cache TTL policies (near-term: 2-6h, far-term: 7d)
+- [x] Add cache lookup before on-demand /search calls
+- [x] Write tests for cache hit/miss with lazy expansion
+- [x] Write tests for TTL policy selection based on date distance
+- [x] Run tests - must pass before task 5
 
 ### Task 5: Verify end-to-end lazy routing and update documentation
-- [ ] Verify all requirements from Overview are implemented
-- [ ] Verify edge cases: closed station fallback, depth limits, cache behavior
-- [ ] Run full test suite (unit tests)
-- [ ] Run linter - all issues must be fixed
-- [ ] Update this plan file when scope changes during implementation
-- [ ] Update README.md if new patterns discovered
+- [x] Verify all requirements from Overview are implemented
+- [x] Verify edge cases: closed station fallback, depth limits, cache behavior
+- [x] Run full test suite (unit tests)
+- [x] Run linter - all issues must be fixed
+- [x] Update this plan file when scope changes during implementation
+- [x] Update README.md if new patterns discovered
 
 ### Task 6: Final verification and plan completion
 - [ ] Verify all checkboxes marked