Subagents, slash commands, skill scaffolder, and discoverability pass (#28)

Growth-focused additions drawn from studying alirezarezvani/claude-skills —
broaden content types beyond skills, lower contribution friction, and improve
discoverability.

Breadth (content types):
- agents/ — 4 Claude Code subagents (pm-partner, sprint-master, cs-guardian,
  launch-captain) that delegate to the strongest skills and run their helper
  scripts to compute results.
- commands/ — 6 slash commands (/prd, /rice, /sprint-plan, /health-scorecard,
  /retro, /exec-summary).
- install.sh --agent claude now installs skills + agents + commands into ~/.claude/.

Contribution UX:
- scripts/new-skill.mjs (npm run new-skill) scaffolds a SKILL.md that already
  passes SkillCheck.
- package.json exposes npm run entry points (new-skill, skillcheck, build:exports,
  build:web, check).

Discoverability:
- Keyword-rich README H1 (Agent Skills for Claude, ChatGPT, Gemini, Cursor,
  Codex & Hermes), subagent/command count badges, a Subagents & Slash Commands
  section, and a Star History chart. Contributing now points at the scaffolder.

CHANGELOG updated. SkillCheck, exports, and web index all verified in sync.


Claude-Session: https://claude.ai/code/session_016JWn5jRD5tcEFKrubjQ6Px

Co-authored-by: Claude <noreply@anthropic.com>

scripts/new-skill.mjs

@@ -0,0 +1,113 @@
+#!/usr/bin/env node
+// Scaffold a new skill that already passes SkillCheck. Lowers the barrier to
+// contributing — fill in the blanks instead of remembering the whole structure.
+//
+// Usage:
+//   node scripts/new-skill.mjs --name churn-forecaster --description "..."
+//   node scripts/new-skill.mjs            # interactive (prompts for the basics)
+//   npm run new-skill -- --name my-skill
+//
+// No dependencies.
+import { writeFileSync, existsSync, mkdirSync } from 'node:fs';
+import { join, dirname } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { createInterface } from 'node:readline/promises';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const root = join(__dirname, '..');
+
+function parseArgs(argv) {
+  const out = {};
+  for (let i = 0; i < argv.length; i++) {
+    const a = argv[i];
+    if (a === '--force') out.force = true;
+    else if (a.startsWith('--')) { out[a.slice(2)] = argv[i + 1]; i++; }
+  }
+  return out;
+}
+
+const titleCase = (name) =>
+  name.split('-').map((w) => w.charAt(0).toUpperCase() + w.slice(1)).join(' ');
+
+function template({ name, title, description }) {
+  return `---
+name: ${name}
+description: "${description}"
+---
+
+# ${title} Skill
+
+One-line summary of the value this skill delivers. <!-- TODO: rewrite -->
+
+## What This Skill Produces
+
+- <!-- TODO: the concrete deliverable(s) this skill outputs -->
+
+## Required Inputs
+
+Ask for (if not already provided):
+- <!-- TODO: the inputs to gather; never invent them -->
+
+## Process
+
+1. <!-- TODO: the steps the skill follows -->
+
+## Output Format
+
+<!-- TODO: a concrete template (headings/tables) of the final artifact -->
+
+## Quality Checks
+
+- [ ] <!-- TODO: a check the output must pass before hand-off -->
+
+## Anti-Patterns
+
+- [ ] Do not <!-- TODO: the mistake this skill prevents -->
+`;
+}
+
+async function resolveInputs(args) {
+  let { name, title, description } = args;
+  const interactive = !name && process.stdin.isTTY;
+  if (interactive) {
+    const rl = createInterface({ input: process.stdin, output: process.stdout });
+    name = (await rl.question('Skill name (lowercase-hyphenated): ')).trim();
+    description = (await rl.question('Description (what / use when / produces): ')).trim();
+    rl.close();
+  }
+  if (!name) throw new Error('Provide --name (lowercase-hyphenated), or run in a terminal for prompts.');
+  if (!/^[a-z0-9]+(-[a-z0-9]+)*$/.test(name)) throw new Error(`Invalid name "${name}". Use lowercase letters, numbers, and hyphens.`);
+  title = title || titleCase(name);
+  // A default description that already satisfies SkillCheck (what / use when / produces).
+  description = description || `Summarise what ${title} does in one line. Use when asked to [trigger phrases the user would say]. Produces [the concrete artifact].`;
+  return { name, title, description };
+}
+
+async function main() {
+  const args = parseArgs(process.argv.slice(2));
+  let inputs;
+  try {
+    inputs = await resolveInputs(args);
+  } catch (e) {
+    console.error(`Error: ${e.message}`);
+    process.exit(1);
+  }
+
+  const dir = join(root, 'skills', inputs.name);
+  const file = join(dir, 'SKILL.md');
+  if (existsSync(file) && !args.force) {
+    console.error(`Error: ${file} already exists (use --force to overwrite).`);
+    process.exit(1);
+  }
+
+  mkdirSync(dir, { recursive: true });
+  writeFileSync(file, template(inputs));
+
+  console.log(`Created skills/${inputs.name}/SKILL.md`);
+  console.log('\nNext:');
+  console.log(`  1. Fill in the TODO sections.`);
+  console.log(`  2. node scripts/skillcheck.mjs        # validate it`);
+  console.log(`  3. node web/build-skills.mjs && node scripts/build-exports.mjs   # refresh generated artifacts`);
+}
+
+main();