refactor: replace n8n package with overlay override

docs/packages/n8n.md

@@ -20,32 +20,24 @@ n8n (pronounced "n-eight-n") is a workflow automation tool that helps you connec
 
 ## Installation
 
+This repository does not publish a standalone `n8n` package. Instead, it provides an overlay that overrides the upstream nixpkgs `n8n` package with a newer pinned release when needed.
+
 ### Via Overlay
 
 ```nix
-{pkgs, ...}: {
+{inputs, pkgs, ...}: {
+  nixpkgs.overlays = [
+    inputs.m3ta-nixpkgs.overlays.default
+    # Or, if you only want package overrides:
+    # inputs.m3ta-nixpkgs.overlays.modifications
+  ];
+
   environment.systemPackages = with pkgs; [
     n8n
   ];
 }
 ```
 
-### Direct Reference
-
-```nix
-{pkgs, ...}: {
-  environment.systemPackages = with pkgs; [
-    inputs.m3ta-nixpkgs.packages.${pkgs.system}.n8n
-  ];
-}
-```
-
-### Run Directly
-
-```bash
-nix run git+https://code.m3ta.dev/m3tam3re/nixpkgs#n8n
-```
-
 ## Usage
 
 ### Basic Usage