v3.27.0

• Added native Codex and Claude Code plugin marketplaces so each host owns skill discovery, updates, disablement, and uninstall.
• Added confirmed, checksum-verified bootstrap of the Go ixf runtime into user-local directories without modifying PATH.
• Consolidated the seven agent skills into one canonical source tree with deterministic host-specific generated plugin packages.
• Added a Claude-only SessionStart routing hint while keeping Codex packages hook-free.
• Extended read-only ixf doctor --json diagnostics for native plugin installation, absent/unknown states, and legacy raw-skill duplicate risk.
• Replaced setup dependency commands with dry-run-first ixf deps install and explicit --apply for optional Mermaid rendering dependencies.
• Removed ixf setup skills, ixf update skills, and the complete ixf setup command family; native host plugins now own skill installation.