v1.7.2 — local index directory fix

Bug Fixes

• local-index: Ensure .context-mode/ parent directory is created before opening code-index.db. better-sqlite3 creates the file but not intermediate directories, causing ctx_local_index / ctx_local_search to fail with "Cannot open database because the directory does not exist" on first use.

Verification

• Build passes (npm run build)
• All 16 local-indexer + searcher tests pass
• CLI local-index, local-search, local-repos verified end-to-end