v0.2.4

Removed

• Dropped the stale memsearch + Milvus scaffolding (Task 120). The kit ships keyword-only and never actually used memsearch, but cmk doctor had two memsearch checks (HC-1 "installed" + HC-7 "reachable") and the install shipped a milvus-deploy Docker stack + a nightly-index cron + "install memsearch" setup docs — confusing users into thinking a semantic backend was required. All of it is gone: cmk doctor now runs 7 checks (HC-1..HC-7) instead of 9, and --mode=semantic/--mode=hybrid report the Layer-5b backend is "not yet shipped" (the choice is deferred — design §9.3.1; the semanticBackend extension seam is kept).