the RaBitQ index is never built automatically and is unused on the bridge search path #4203

memory/rabitq-index.ts:286 shouldRebuildRabitq() has no callers on main. The index is built only by an
explicit embeddings_rabitq_build (mcp-tools/embeddings-tools.ts:1003). searchRabitq is used as a
pre-filter only on the sql.js path (memory/memory-initializer.ts:3215). With the bridge, the default with
native better-sqlite3, memory_search reports sqlite (bridge, brute-force cosine) and never uses it.

Expected: build and rebuild on the threshold that helper already computes, and use it from the bridge
path, or document that it is sql.js-only.

Environment: found on ruflo 3.56.9 (global npm), Node v24.21.0, Linux (WSL2), Claude Code 2.1.295, ruflo-core plugin MCP. The same code is on main at 1882006 (3.56.10); line numbers are v3/@claude-flow/cli/src/ on main unless a plugin path is given.