Add 78 new tests targeting high-impact uncovered modules: - tests/test_search_advanced.py (23 tests): InvertedIndex CRUD, search/advanced_search/suggest functions, tag/title indexing - tests/test_indexer_advanced.py (15 tests): hooks, file CRUD, path index, lookup, generation counter - tests/test_modules.py (40 tests): audit, history, rate limit, saved searches, vault settings, webhooks, share Coverage improvements: ratelimit.py: 80% → 100% share.py: 24% → 97% saved_searches: 37% → 95% history.py: 26% → 86% audit.py: 0% → 85% search.py: 44% → 82% webhooks.py: 31% → 67% vault_settings: 31% → 69% indexer.py: 47% → 65% Overall: 35% → 49%