Search returned empty results due to two issues:
1. vectorStore.js called .search() but LanceDB v0.4 renamed it to .vectorSearch()
2. Files were never bulk-indexed on startup — only on change events

Also adds always-visible [OVCS] log messages for indexing status, enhances
/search/stats with additional diagnostics, and makes /search/reindex fall
back to filesystem walking when the RxDB collection is empty.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>