v0.18.2 — setup always overwrites in default multi-target mode

Fixed

• research-pipeline setup now overwrites stale skill/agent copies in default multi-target mode. Previously, running setup after pipx upgrade would silently skip already-installed directories (e.g. ~/.agents/skills/daily-ai-intelligence/, ~/.claude/skills/…) leaving stale files. Fix: pass force or default_multi_target to _install_directory and _install_agent_files so default mode has upgrade semantics. Single-target mode still requires explicit --force.