feat: add author skill — workflow YAML design guide

Adds 'uwf skill author' for agents/humans designing workflow definitions.
Covers: YAML structure, role definition, frontmatter schema design,
graph routing, edge prompts, self-testing, and common pitfalls.

Refs #539

packages/cli-workflow/src/cli.ts

@@ -19,6 +19,7 @@ import { cmdSetup, cmdSetupInteractive } from "./commands/setup.js";
 import {
   cmdSkillActor,
   cmdSkillArchitecture,
+  cmdSkillAuthor,
   cmdSkillCli,
   cmdSkillList,
   cmdSkillModerator,
@@ -512,6 +513,13 @@ skill
     console.log(cmdSkillActor());
   });
 
+skill
+  .command("author")
+  .description("Print the author reference (workflow YAML design guide)")
+  .action(() => {
+    console.log(cmdSkillAuthor());
+  });
+
 skill
   .command("moderator")
   .description("Print the moderator reference")