- Replace docs/sheet/slides with kb-extraction in default features (~4-6min compile time savings, ~300MB less disk)
- Add kb-extraction feature using zip+quick-xml+calamine for lightweight KB extraction
- Split document_processor.rs (829 lines) into mod.rs+types.rs+ooxml_extract.rs+rtf.rs
- Move DOCX/PPTX ZIP-based extraction to document_processor::ooxml_extract (no ooxmlsdk needed)
- Remove dead code: save_docx_preserving(), save_pptx_preserving() (zero callers)
- Fix dep: prefix for optional dependencies in feature definitions
- DriveMonitor: full S3 sync, ETag change detection, KB incremental indexing, config.csv sync
- ConfigManager: real DB reads from bot_configuration table
- 0 warnings, 0 errors on both default and full feature builds
