Add minimal server install profile

[marcfranquesa]

The current bootstrap path effectively installs the whole dotfiles tree, which is too much for servers.

Proposal:

• Add a server install profile that links only shell/git/tmux/nvim basics.
• Keep workstation-only helpers like open-compiled, _zathura_inverse, zathura, Ghostty, TeX/PDF workflow pieces, Docker/Colima, and macOS/Homebrew-specific setup out of the server profile.
• Split package lists so server installs only essentials such as git, zsh, stow, tmux, neovim, ripgrep, fzf, and wget.
• Guard interactive-only behavior, especially automatic tmux-init startup.
• Make tmux server-safe by avoiding unconditional pbcopy and local plugin assumptions.

Likely shape:

bootstrap/install.sh server
bootstrap/install.sh workstation

Acceptance criteria:

• server profile can be installed on a headless Linux server without GUI/macOS tools.
• Workstation behavior remains available through a separate profile.
• Existing local helper scripts are not linked unless their profile needs them.