Add Python 3.13 installation

- Install python3.13 package to match dotfiles alias
- Ensures 'python' alias points to working Python 3.13

🤖 Generated with [Claude Code](https://claude.ai/code)

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

post-install.sh

@@ -158,7 +158,7 @@ fi
 echo "[+] Installing additional packages..."
 dnf install -y \
   clevis clevis-luks tpm2-tools tpm2-tss \
-  tmux neovim python3-pip npm \
+  tmux neovim python3-pip python3.13 npm \
   tree gcc make autoconf automake tar bzip2 || exit 1