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-samples.mjs

@@ -0,0 +1,69 @@
+#!/usr/bin/env node
+// Builds web/samples.json from examples/samples/*.md for the sample-output gallery.
+// Each sample file has frontmatter (skill, title, input, source) + the output body.
+//
+// Build the gallery data:   node scripts/build-samples.mjs
+// Generate a new sample:     ANTHROPIC_API_KEY=sk-ant-... node scripts/build-samples.mjs --generate <skill>
+//   (runs the skill on its eval case input and writes examples/samples/<skill>.md)
+import { readFileSync, writeFileSync, readdirSync, existsSync, mkdirSync } from 'node:fs';
+import { join, dirname } from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const root = join(dirname(fileURLToPath(import.meta.url)), '..');
+const samplesDir = join(root, 'examples', 'samples');
+
+function parseFrontmatter(text) {
+  const m = text.match(/^---\n([\s\S]*?)\n---\n?([\s\S]*)$/);
+  if (!m) return { meta: {}, body: text };
+  const meta = {};
+  for (const line of m[1].split('\n')) {
+    const kv = line.match(/^(\w[\w-]*):\s*(.*)$/);
+    if (kv) {
+      let v = kv[2].trim();
+      if ((v.startsWith('"') && v.endsWith('"')) || (v.startsWith("'") && v.endsWith("'"))) v = v.slice(1, -1);
+      meta[kv[1]] = v;
+    }
+  }
+  return { meta, body: m[2].trim() };
+}
+
+async function generate(skillName) {
+  const { complete, parseSkill } = await import('../bin/lib/anthropic.mjs');
+  const apiKey = process.env.ANTHROPIC_API_KEY;
+  if (!apiKey) { console.error('Set ANTHROPIC_API_KEY to generate.'); process.exit(1); }
+  const skillFile = join(root, 'skills', skillName, 'SKILL.md');
+  if (!existsSync(skillFile)) { console.error(`Unknown skill: ${skillName}`); process.exit(1); }
+  const { body } = parseSkill(readFileSync(skillFile, 'utf8'));
+  const cases = JSON.parse(readFileSync(join(root, 'evals', 'cases.json'), 'utf8')).cases;
+  const input = (cases.find((c) => c.skill === skillName) || {}).input;
+  if (!input) { console.error(`No eval case input for ${skillName}; add one to evals/cases.json first.`); process.exit(1); }
+  const system = body + '\n\n---\nExecute this skill now on the input below and produce the complete output. Do not ask questions.';
+  const output = await complete({ apiKey, model: 'claude-sonnet-4-6', system, messages: [{ role: 'user', content: input }], maxTokens: 4096 });
+  const title = skillName.split('-').map((w) => w[0].toUpperCase() + w.slice(1)).join(' ');
+  if (!existsSync(samplesDir)) mkdirSync(samplesDir, { recursive: true });
+  const fm = `---\nskill: ${skillName}\ntitle: ${title}\ninput: ${JSON.stringify(input)}\nsource: generated by claude-sonnet-4-6\n---\n\n${output.trim()}\n`;
+  writeFileSync(join(samplesDir, `${skillName}.md`), fm);
+  console.log(`Wrote examples/samples/${skillName}.md`);
+}
+
+const genIdx = process.argv.indexOf('--generate');
+if (genIdx !== -1) {
+  await generate(process.argv[genIdx + 1]);
+}
+
+// Build samples.json
+const samples = [];
+if (existsSync(samplesDir)) {
+  for (const f of readdirSync(samplesDir).filter((f) => f.endsWith('.md')).sort()) {
+    const { meta, body } = parseFrontmatter(readFileSync(join(samplesDir, f), 'utf8'));
+    samples.push({
+      skill: meta.skill || f.replace(/\.md$/, ''),
+      title: meta.title || meta.skill || f,
+      input: meta.input || '',
+      source: meta.source || '',
+      output: body,
+    });
+  }
+}
+writeFileSync(join(root, 'web', 'samples.json'), JSON.stringify({ count: samples.length, samples }));
+console.log(`Wrote web/samples.json — ${samples.length} sample outputs.`);