mnemostack 0.4.3

Fix: vector_floor is now applied post-rerank, so floored top raw-cosine vector candidates are guaranteed in the final result set after reranking and top_k slicing. Floored items are appended beyond top_k, reranked winners are preserved, results are deduped by id, and the default vector_floor=0 remains a no-op. This completes the 0.4.2 half-measure where the floor was applied pre-rerank and could be re-sunk by the final slice. (PR #50)

Fix: the reranker prompt now requests a full reordered list of all candidate ids instead of only the relevant subset. On the real Gemini Flash path this raised ids returned from about 4/25 to 25/25, so the reranker now reorders the full candidate set instead of only a tiny head. Output budget was scaled accordingly. (PR #51)