docs: add n8n node to implementations

Author: blackwell-systems

README.md

@@ -206,6 +206,7 @@ GCF wins 13/15 datasets on the expanded [token efficiency benchmark](https://git
 | Claude Code Plugin | `/plugin install` | [gcf-claude-plugin](https://github.com/blackwell-systems/gcf-claude-plugin) (one-command install, session stats hook) |
 | Codex Plugin | `codex plugin add` | [gcf-codex-plugin](https://github.com/blackwell-systems/gcf-codex-plugin) (one-command install, session stats hook) |
 | VS Code | `ext install blackwell-systems.gcf-vscode` | [gcf-vscode](https://marketplace.visualstudio.com/items?itemName=blackwell-systems.gcf-vscode) (syntax highlighting) |
+| n8n | `npm install n8n-nodes-gcf` | [gcf-n8n-nodes](https://github.com/blackwell-systems/gcf-n8n-nodes) (workflow encode/decode) |
 | Tree-sitter | `npm install tree-sitter-gcf` | [tree-sitter-gcf](https://github.com/blackwell-systems/tree-sitter-gcf) |
 
 Zero runtime dependencies. MIT licensed. All implementations support both generic profile (`encodeGeneric`) and graph profile (`encode`). CLI included in all 6 languages.