feat: workflow recipes, eval badges, one-click MCP, playground upgrades, sample gallery, skill-of-the-week

Signature features that turn breadth (174 skills) into a differentiated product:

- Workflow recipes: 5 cross-profession chains (workflows.json) that pass each
  output forward — slash commands (/ship-a-feature etc.), WORKFLOWS.md generated
  by scripts/build-workflows.mjs, README + MCP (list_workflows/get_workflow) wired
- Eval-backed quality: real per-skill scores from evals/results.json surfaced as
  badges in the playground and an honest README section (6 scored skills)
- One-click MCP: 'claude mcp add' install + workflow tools, works in any MCP client
- Playground: 'which skill?' recommender, with/without compare toggle, shareable
  ?skill= deep-links with prefilled inputs
- Sample-output gallery: hand-written examples for the hero five + generator
  (scripts/build-samples.mjs) + web/examples.html
- Skill-of-the-week: scheduled workflow + script that composes X/LinkedIn posts
  and posts to an optional webhook

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/build-workflows.mjs

@@ -0,0 +1,70 @@
+#!/usr/bin/env node
+// Generates WORKFLOWS.md from workflows.json and validates that every recipe
+// references a real skill (skills/<skill>/SKILL.md) and ships a slash command
+// (commands/<id>.md). Run: node scripts/build-workflows.mjs  [--check]
+// --check exits non-zero if WORKFLOWS.md is out of sync (for CI).
+import { readFileSync, writeFileSync, existsSync } from 'node:fs';
+import { join, dirname } from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const root = join(dirname(fileURLToPath(import.meta.url)), '..');
+const { workflows } = JSON.parse(readFileSync(join(root, 'workflows.json'), 'utf8'));
+
+// --- Validate ---
+const errors = [];
+for (const w of workflows) {
+  if (!existsSync(join(root, 'commands', `${w.id}.md`))) errors.push(`Missing command file: commands/${w.id}.md`);
+  for (const step of w.steps) {
+    if (!existsSync(join(root, 'skills', step.skill, 'SKILL.md'))) errors.push(`${w.id}: unknown skill "${step.skill}"`);
+  }
+}
+if (errors.length) {
+  console.error('Workflow validation failed:\n  ' + errors.join('\n  '));
+  process.exit(1);
+}
+
+// --- Render WORKFLOWS.md ---
+const lines = [];
+lines.push('# 🧩 Workflow Recipes', '');
+lines.push('> **Skills you can chain.** A recipe runs several skills in sequence and *passes each output forward as context* for the next — so a fuzzy idea comes out the other end as a finished, joined-up set of artifacts. No other skills library chains across professions like this.', '');
+lines.push('Run one as a slash command in Claude Code (e.g. `/ship-a-feature a referral program for B2B users`), or fetch it over MCP with the `get_workflow` tool.', '');
+lines.push('<!-- Generated from workflows.json by scripts/build-workflows.mjs — do not edit by hand. -->', '');
+lines.push(`There are **${workflows.length} recipes** today:`, '');
+
+// Index table
+lines.push('| Recipe | Command | Lifecycle | Chains |');
+lines.push('|--------|---------|-----------|--------|');
+for (const w of workflows) {
+  lines.push(`| **${w.name}** | \`${w.command}\` | ${w.lifecycle} | ${w.steps.length} skills |`);
+}
+lines.push('');
+
+// Per-recipe detail
+for (const w of workflows) {
+  lines.push(`## ${w.name} — \`${w.command}\``, '');
+  lines.push(`*${w.lifecycle}* · ${w.summary}`, '');
+  const chain = w.steps.map((s) => `\`${s.skill}\``).join(' → ');
+  lines.push(chain, '');
+  w.steps.forEach((s, i) => {
+    lines.push(`${i + 1}. **${s.skill}** → produces ${s.produces}.`);
+  });
+  lines.push('');
+}
+
+lines.push('---', '');
+lines.push('**Add your own:** define it in [`workflows.json`](workflows.json), add a matching `commands/<id>.md`, and run `node scripts/build-workflows.mjs`. Recipes are just composition — every step is an existing skill you can already run on its own.', '');
+
+const md = lines.join('\n');
+const target = join(root, 'WORKFLOWS.md');
+
+if (process.argv.includes('--check')) {
+  const current = existsSync(target) ? readFileSync(target, 'utf8') : '';
+  if (current !== md) {
+    console.error('WORKFLOWS.md is out of sync with workflows.json. Run: node scripts/build-workflows.mjs');
+    process.exit(1);
+  }
+  console.log('WORKFLOWS.md is in sync.');
+} else {
+  writeFileSync(target, md);
+  console.log(`Wrote WORKFLOWS.md — ${workflows.length} recipes, all skills + commands validated.`);
+}