v0.161.0

Feat

• search: expose optional reranking on both search entrypoints
• search: distinguish a routine rerank skip from a real failure
• search: add cross-encoder rerank machinery (unused until wired)
• observability: measure both semantic-search entrypoints equally

Fix

• search: keep unscored rows behind reranked ones in the HTTP re-sort
• search: cut the rerank pool back before verify-on-read on the HTTP path
• search: correct total_found for doc_types, and stop skips reading as outages
• search: carry rerank_score through context expansion
• search: test the granularity echo, use the constant, satisfy Sonar
• search: record failed rerank latency, log truncation, split entry parsing
• search: make the grouped rerank-pool precedence explicit and tested
• observability: bound the algorithm metric label against caller input
• observability: record vector_search errors, and cover the MCP metric paths
• observability: keep the algorithm label stable, and meter the third entrypoint
• observability: label HTTP search usage with the http surface
• search: report the real group limit on the qdrant query span
• search: request exact group count in grouped hybrid search