personal memory agent

install: auto-add ~/.local/bin to shell PATH via userpath master

make install-service now calls userpath.append() after writing the sol symlink, adding bash/zsh/fish rc blocks when needed and printing a manual-fallback message if that fails. Bump the Python dependency to userpath>=1.9.2,<2. Co-Authored-By: Codex <codex@openai.com>