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>

web/build-skills.mjs

@@ -20,6 +20,26 @@ const experimentalSet = new Set(TIERS.experimental);
 const tierFor = (name) =>
   productionSet.has(name) ? 'production' : experimentalSet.has(name) ? 'experimental' : 'stable';
 
+// --- Eval scores (from evals/results.json) ---
+// Average the per-model "overall" (a 0–5 rubric score) for each scored skill.
+// Only skills with eval cases get a score; the rest stay unscored (honest).
+const evalScores = {};
+const evalsFile = join(root, 'evals', 'results.json');
+if (existsSync(evalsFile)) {
+  try {
+    const acc = {};
+    for (const r of JSON.parse(readFileSync(evalsFile, 'utf8')).results || []) {
+      (acc[r.skill] ||= []).push(r.overall);
+    }
+    for (const [skill, arr] of Object.entries(acc)) {
+      evalScores[skill] = {
+        score: Math.round((arr.reduce((a, b) => a + b, 0) / arr.length) * 10) / 10,
+        runs: arr.length,
+      };
+    }
+  } catch { /* leave unscored on parse error */ }
+}
+
 // --- Map each skill name -> plugin bundle (for grouping/filtering) ---
 const skillToPlugin = {};
 if (existsSync(pluginsDir)) {
@@ -109,6 +129,7 @@ for (const name of readdirSync(skillsDir)) {
     summary: summarize(meta.description || ''),
     plugin: skillToPlugin[name] || 'other',
     tier: tierFor(name),
+    eval: evalScores[meta.name || name] || null,
     inputs: parseInputs(body),
     instructions: body.trim(),
   });