Remove hardcoded SSH_AUTH_SOCK paths and rely on external env vars

[gbastkowski]

The Emacs configuration currently hardcodes SSH_AUTH_SOCK paths for different operating systems:

(cond ((eq system-type 'gnu/linux) (setenv "SSH_AUTH_SOCK" "/run/user/1000/gnupg/S.gpg-agent.ssh"))
      ((eq system-type 'darwin)    (setenv "SSH_AUTH_SOCK" "/Users/gunnar.bastkowski/.gnupg/S.gpg-agent.ssh"))
      (t                           (setenv "SSH_AUTH_SOCK" "")))

This code should be removed and instead rely on external environment variables that are properly set by the shell/system. This would make the configuration more portable and maintainable.

Benefits:

• More portable across different systems and users
• Eliminates hardcoded paths
• Follows Unix philosophy of letting external tools handle environment setup
• Reduces configuration complexity

Files affected:

• emacs/.doom.d/config.org (lines 14-17)
• emacs/.doom.d/config.el (lines 3-5)