Initial dotfiles commit

Laptop config: zsh, emacs (with WSL detection for work), ghostty, tmux, ranger,
newsboat, neomutt + mbsync + msmtp (Outlook OAuth2), neomutt signature.
Work config: emacs with C#/TS/JS/CSS/HTML dev settings for WSL.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

laptop/.zshenv

@@ -0,0 +1,5 @@
+export BROWSER=firefox
+export EDITOR="emacsclient -t -a \"\""
+export VISUAL="emacsclient -c -a \"\""
+export TERMINAL=ghostty
+export MAILER=neomutt