Remove asdf after mise trial period

[tmr08c]

mise has been added alongside asdf (#51). After confirming it works well, remove asdf and its configuration.

asdf integration points to clean up

• asdf/ directory (path.zsh, fpath.zsh, install.sh, asdfrc.symlink)
• homebrew/Brewfile.symlink — remove brew "asdf"
• zsh/zprofile.symlink — remove asdf sourcing
• zsh/zshrc.symlink — remove direnv() { asdf exec direnv "$@"; } alias, remove asdf-direnv/zshrc source
• bash/bash_profile.symlink — remove ASDF_DIR, asdf.sh, and completion sourcing
• bash/bashrc.symlink — remove source /usr/local/opt/asdf/asdf.sh
• config.symlink/fish/config.fish — remove asdf.fish sourcing and stale tabtab lines
• config.symlink/fish/completions/asdf.fish — delete
• config.symlink/direnv/lib/use_asdf.sh — delete
• Update CLAUDE.md references from asdf to mise
• Add mise activation to bash and fish shells
• Update comment URLs in node/default-npm-packages.symlink and ruby/defaults-gems.symlink

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