Release v5.1.0-rc16

What's Changed

• fix: loop orphaned Unit cleanup in dd-only export to catch all orphans
• Merge branch 'main' of github.com:Simon-McIntosh/imas-codex
• fix: prevent orphaned temp Neo4j processes blocking graph exports
• fix: prevent orphaned temp Neo4j processes blocking graph exports
• fix: handle ToolError in search tool tests for no-torch environments
• test: guard server formatter imports against rename breakage
• fix: complete cluster labeling on build skip and enforce CI quality gates
• fix: upgrade fastmcp >=3.2.0 for CVE-2026-32871, CVE-2026-27124, CVE-2025-64340
• fix: smoke-test must pass before container build proceeds
• fix: allow workflow_dispatch and tolerate graph-quality failures in container build
• fix: update short terms test for dict type and reduce temp Neo4j memory
• fix: reduce temp Neo4j memory to prevent OOM and improve health endpoint
• feat: expand physics abbreviations for vector search instead of skipping
• test: adjust benchmark for summary exclusion and abbreviation gaps
• refactor: rename include_summary to include_summary_ids for clarity
• test: fix plasma_current_finds_ip for description-only embeddings
• test: add unit tests for STRUCTURE search result child expansion
• feat: exclude summary IDS from search results by default
• test: update embed text quality tests for description-only embeddings
• fix: adaptive cluster filtering for long multi-word queries
• test: add benchmark queries for A/B test gap scenarios
• fix: add phrase-aware BM25 query rewriting for multi-word searches
• fix: remove path prefix from embeddings and gate vector search for short terms
• fix: identifiers tests work with CI fixture graph
• feat: release CLI defaults to origin for RC, upstream for final
• fix: move identifiers test to graph_mcp for CI Neo4j
• fix: ranking pipeline overhaul for search quality

Full Changelog: v5.1.0-rc8...v5.1.0-rc16