feat: add Pi provider support, fix community health files, recategorize /onboard

- Add first-class Pi (pi.dev) provider with transformer, tests, and build integration
- Fix CODEOWNERS username (@paulbakaus → @pbakaus)
- Add missing providers to issue/PR templates (Copilot, Kiro, OpenCode, Pi)
- Add Pi and OpenCode logos to homepage hero and install sections
- Move /onboard from "system" to "enhancement" category
- Update README and DEVELOP.md with all supported providers

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/lib/transformers/index.js

@@ -5,3 +5,4 @@ export { transformCodex } from './codex.js';
 export { transformAgents } from './agents.js';
 export { transformKiro } from './kiro.js';
 export { transformOpenCode } from "./opencode.js";
+export { transformPi } from './pi.js';

scripts/lib/transformers/pi.js

@@ -0,0 +1,65 @@
+import path from 'path';
+import { cleanDir, ensureDir, writeFile, generateYamlFrontmatter, replacePlaceholders, prefixSkillReferences } from '../utils.js';
+
+/**
+ * Pi Transformer (Skills Only)
+ *
+ * All skills output to .pi/skills/{name}/SKILL.md
+ * Frontmatter: name, description, license, compatibility, metadata
+ *
+ * @param {Array} skills - All skills (including user-invokable ones)
+ * @param {string} distDir - Distribution output directory
+ * @param {Object} patterns - Design patterns data (unused)
+ * @param {Object} options - Optional settings
+ * @param {string} options.prefix - Prefix to add to skill names (e.g., 'i-')
+ * @param {string} options.outputSuffix - Suffix for output directory (e.g., '-prefixed')
+ */
+export function transformPi(skills, distDir, patterns = null, options = {}) {
+  const { prefix = '', outputSuffix = '' } = options;
+  const piDir = path.join(distDir, `pi${outputSuffix}`);
+  const skillsDir = path.join(piDir, '.pi/skills');
+
+  cleanDir(piDir);
+  ensureDir(skillsDir);
+
+  const allSkillNames = skills.map(s => s.name);
+  const commandNames = skills.filter(s => s.userInvokable).map(s => `${prefix}${s.name}`);
+  let refCount = 0;
+  for (const skill of skills) {
+    const skillName = `${prefix}${skill.name}`;
+    const skillDir = path.join(skillsDir, skillName);
+
+    const frontmatterObj = {
+      name: skillName,
+      description: skill.description,
+    };
+
+    if (skill.license) frontmatterObj.license = skill.license;
+    if (skill.compatibility) frontmatterObj.compatibility = skill.compatibility;
+    if (skill.metadata) frontmatterObj.metadata = skill.metadata;
+
+    const frontmatter = generateYamlFrontmatter(frontmatterObj);
+    let skillBody = replacePlaceholders(skill.body, 'pi', commandNames);
+    if (prefix) skillBody = prefixSkillReferences(skillBody, prefix, allSkillNames);
+    const content = `${frontmatter}\n\n${skillBody}`;
+    const outputPath = path.join(skillDir, 'SKILL.md');
+    writeFile(outputPath, content);
+
+    // Copy reference files if they exist
+    if (skill.references && skill.references.length > 0) {
+      const refDir = path.join(skillDir, 'reference');
+      ensureDir(refDir);
+      for (const ref of skill.references) {
+        const refOutputPath = path.join(refDir, `${ref.name}.md`);
+        const refContent = replacePlaceholders(ref.content, 'pi');
+        writeFile(refOutputPath, refContent);
+        refCount++;
+      }
+    }
+  }
+
+  const userInvokableCount = skills.filter(s => s.userInvokable).length;
+  const refInfo = refCount > 0 ? ` (${refCount} reference files)` : '';
+  const prefixInfo = prefix ? ` [${prefix}prefixed]` : '';
+  console.log(`✓ Pi${prefixInfo}: ${skills.length} skills (${userInvokableCount} user-invokable)${refInfo}`);
+}