Initial commit: combined darwin + guix-linux home-manager flake

Supersedes nix-dotfiles (darwin) and guix-dotfiles' ad-hoc
nix-home-manager flake (linux). See README.md/MIGRATION.md.

1 files changed, 44 insertions, 0 deletions

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+# nix-combined
+
+One flake, two targets:
+
+- `darwinConfigurations.RyanMac` - the mac system (nix-darwin + home-manager),
+  equivalent to what `nix-dotfiles` built.
+- `homeConfigurations.ryan` - standalone home-manager for `x86_64-linux`,
+  meant to run *on top of* Guix System as the home-manager substitute for
+  what `guix-dotfiles/home-config/home-configuration.scm` used to fully own.
+  Guix still owns the system config, package management, and three home
+  services that need shepherd (pipewire, dbus, downloads-gc) - see
+  `MIGRATION.md`.
+
+`users/ryan/common.nix` holds everything shared by both (git, ssh, gpg-agent,
+starship, zsh, zen-browser, neovim). `darwin.nix` and `linux.nix` hold the
+platform-specific rest.
+
+## Darwin
+
+```
+sudo nix run --extra-experimental-features "nix-command flakes" github:nix-darwin/nix-darwin -- switch --flake .#RyanMac \
+  --option "extra-substituters" "https://virby-nix-darwin.cachix.org" \
+  --option "extra-trusted-public-keys" "virby-nix-darwin.cachix.org-1:z9GiEZeBU5bEeoDQjyfHPMGPBaIQJOOvYOOjGMKIlLo="
+```
+
+Subsequent rebuilds: `rebuild` (zsh alias) or
+`sudo darwin-rebuild switch --flake ~/.config/nix/.`
+
+## Linux (Guix)
+
+Requires `experimental-features = nix-command flakes` in
+`~/.config/nix/nix.conf` (guix-dotfiles already symlinks this in).
+
+```
+nix run --extra-experimental-features "nix-command flakes" home-manager -- switch --flake .#ryan
+```
+
+Subsequent rebuilds: `rebuild` (zsh alias) or
+`home-manager switch --flake ~/.config/home-manager#ryan`.
+
+See `MIGRATION.md` for what needs to change in `guix-dotfiles` for this to
+slot in cleanly (symlink target, overlapping config entries to remove, the
+zsh login-shell switch), what stays Guix-native and why, and what got
+dropped as dead weight along the way.