docs: add portable LLM workflow skill

README.md

@@ -270,6 +270,15 @@ The generated launcher snippets contain only `command`, `args`,
 `GITEA_MCP_CONFIG`, and `GITEA_MCP_PROFILE` — never a token or password.
 </details>
 
+### Portable LLM workflow skill
+
+Reusable LLM operating rules are packaged as a portable skill at
+[`skills/llm-project-workflow/SKILL.md`](skills/llm-project-workflow/SKILL.md).
+It documents issue-first work, isolated branch worktrees, no self-review or
+self-merge, profile safety, fail-closed behavior, merge cleanup, and recovery
+patterns. Copy the `skills/llm-project-workflow/` directory into other projects
+that should use the same workflow.
+
 <details>
 <summary><strong>Codex / non-MCP tools</strong></summary>