- Extract key management logic into keys/flake-module.nix
- Organize keys into subfolders: ssh/, pgp/, age/
- Simplify extension stripping (remove everything after first dot)
- Remove inline key definitions from flake.nix

- Extract package autoimport logic into 5pkgs/flake-module.nix
- Support both package.nix (preferred) and default.nix
- Show deprecation warning when using default.nix

- Replace symlinkJoin with custom multiOutputSymlinkJoin that correctly handles multi-output packages
- Preserve man pages, docs, and other outputs by symlinking from original package outputs
- Fix zsh build while maintaining access to man pages via .man output
- All wrapper tools (mpv, mutt, zsh) now build successfully with full output preservation