简化stable/unstable切换的方式；增加兼容性代码，根据版本引用

flake.nix

@@ -7,6 +7,19 @@
       useremail = "reizero@live.com";
       sourcepath = "/home/${username}/.nix";
       libs = import ./libs;
+
+      nixos = {
+        stable = {
+          nixpkgs = nixpkgs;
+          home-manager = home-manager;
+          version = "24.11";
+        };
+        unstable = {
+          nixpkgs = nixpkgs-unstable;
+          home-manager = home-manager-unstable;
+          version = "25.05";
+        };
+      };
     in
     rec {
       # Your custom packages and modifications, exported as overlays
@@ -20,7 +33,7 @@
           (profile: {
             name = profile;
             value = import ./profiles/${profile} {
-              inherit self inputs outputs libs sourcepath username useremail;
+              inherit self inputs outputs libs nixos sourcepath username useremail;
             };
           })
           (attrNames (readDir ./profiles))