lib/services: move portable service infrastructure out of nixos/

Move the portable modular service base from
nixos/modules/system/service/portable/ to lib/services/, making it
importable by any module system (home-manager, nix-darwin) without
reaching into the nixos/ tree.

Moved files: service.nix, lib.nix, config-data.nix, config-data-item.nix,
test.nix. All external references updated (systemd/system.nix,
doc/manual/default.nix, assertions.nix, README.md).

No functional changes - only import paths differ.

lib/services/config-data-item.nix

@@ -1,4 +1,4 @@
-# Tests in: ../../../../tests/modular-service-etc/test.nix
+# Tests in: ../../nixos/tests/modular-service-etc/test.nix
 # This file is a function that returns a module.
 pkgs:
 {

lib/services/config-data.nix

@@ -1,4 +1,4 @@
-# Tests in: ../../../../tests/modular-service-etc/test.nix
+# Tests in: ../../nixos/tests/modular-service-etc/test.nix
 
 # Non-modular context provided by the modular services integration.
 { pkgs }:

lib/services/service.nix

@@ -16,8 +16,8 @@ in
   # https://nixos.org/manual/nixos/unstable/#modular-services
   _class = "service";
   imports = [
-    ../../../../../modules/generic/meta-maintainers.nix
-    ../../../misc/assertions.nix
+    ../../modules/generic/meta-maintainers.nix
+    ../../nixos/modules/misc/assertions.nix
     (lib.modules.importApply ./config-data.nix { inherit pkgs; })
   ];
   options = {

lib/services/test.nix

@@ -1,7 +1,7 @@
 # Run:
-#   nix-instantiate --eval nixos/modules/system/service/portable/test.nix
+#   nix-instantiate --eval lib/services/test.nix
 let
-  lib = import ../../../../../lib;
+  lib = import ../.;
 
   inherit (lib) mkOption types;
 

nixos/doc/manual/default.nix

@@ -134,7 +134,7 @@ let
     inherit
       (evalModules {
         modules = [
-          (modules.importApply ../../modules/system/service/portable/service.nix {
+          (modules.importApply ../../../lib/services/service.nix {
             pkgs = throw "nixos docs / portableServiceOptions: Do not reference pkgs in docs";
           })
         ];

nixos/modules/misc/assertions.nix

@@ -34,5 +34,5 @@
   };
   # impl of assertions is in
   # - <nixpkgs/nixos/modules/system/activation/top-level.nix>
-  # - <nixpkgs/nixos/modules/system/service/portable/lib.nix>
+  # - <nixpkgs/lib/services/lib.nix>
 }

nixos/modules/system/service/README.md

@@ -43,7 +43,7 @@ Many services implement automatic reloading or reloading on e.g. `SIGUSR1`, but
 
 ### Service Manager Integration
 
-- **Portable base**: The `configData` interface is declared in `portable/config-data.nix`, making it available to all service manager implementations.
+- **Portable base**: The `configData` interface is declared in `lib/services/config-data.nix`, making it available to all service manager implementations.
 
 - **Systemd integration**: The systemd implementation (`systemd/system.nix`) maps `configData` entries to `environment.etc` entries under `/etc/system-services/`.
 
@@ -66,11 +66,11 @@ The modular service infrastructure avoids exposing `pkgs` as a module argument t
 
 ### Implementation
 
-- **Portable layer**: Service modules in `portable/` do not receive `pkgs` as a module argument. Any required derivations must be provided by the caller.
+- **Portable layer**: Service modules in `lib/services/` do not receive `pkgs` as a module argument. Any required derivations must be provided by the caller.
 
 - **Systemd integration**: The `systemd/system.nix` module imports `config-data.nix` as a function, providing `pkgs` in lexical closure:
   ```nix
-  (import ../portable/config-data.nix { inherit pkgs; })
+  (import lib/services/config-data.nix { inherit pkgs; })
   ```
 
 - **Service modules**:

nixos/modules/system/service/systemd/system.nix

@@ -15,7 +15,7 @@ let
     mapAttrsToList
     ;
 
-  portable-lib = import ../portable/lib.nix { inherit lib; };
+  portable-lib = import ../../../../../lib/services/lib.nix { inherit lib; };
 
   dash =
     before: after: