docs: add search configuration and vector storage performance guides - Add configuration/Search-Configuration.md (pgvector iterative scanning, metadata filtering, examples) - Add performance/vector-storage-performance.md (indexing, tuning, benchmarks) - Remove maintenance/Path-Migration.md and replace "Maintenance" with "Performance" in Home.md and _Sidebar.md - Update usage/search-api-guide.md to document pgvector iterative scanning, new response fields (file_types, iterative_scan_used) and recommend SQL-level filters

Anthony-Bible committed Nov 21, 2025