ci(workflows): add skill sync and validation workflows

- Add sync-claude-plugin workflow to auto-update marketplace.json when skills change
- Add validate-skill workflow to validate SKILL.md files on push/PR
- Add sync-marketplace.js script for skill discovery and count updates

.github/scripts/sync-marketplace.js

@@ -0,0 +1,67 @@
+#!/usr/bin/env node
+/**
+ * Sync marketplace.json with skills directory.
+ *
+ * Scans the skills/ directory for valid skills (directories containing SKILL.md)
+ * and updates marketplace.json to match.
+ */
+
+const fs = require("fs");
+const path = require("path");
+
+const SKILLS_DIR = "skills";
+const MARKETPLACE_FILE = ".claude-plugin/marketplace.json";
+
+function getSkillsFromDirectory() {
+  if (!fs.existsSync(SKILLS_DIR)) {
+    return [];
+  }
+
+  return fs
+    .readdirSync(SKILLS_DIR, { withFileTypes: true })
+    .filter((entry) => {
+      if (!entry.isDirectory()) return false;
+      const skillFile = path.join(SKILLS_DIR, entry.name, "SKILL.md");
+      return fs.existsSync(skillFile);
+    })
+    .map((entry) => `./${SKILLS_DIR}/${entry.name}`)
+    .sort();
+}
+
+function updateSkillCount(description, count) {
+  return description.replace(/\d+ marketing skills/, `${count} marketing skills`);
+}
+
+function main() {
+  const currentSkills = getSkillsFromDirectory();
+
+  const marketplace = JSON.parse(fs.readFileSync(MARKETPLACE_FILE, "utf8"));
+  const plugin = marketplace.plugins[0];
+  const existingSkills = plugin.skills || [];
+
+  // Check if update needed
+  if (JSON.stringify(currentSkills) === JSON.stringify(existingSkills)) {
+    console.log("marketplace.json is already in sync");
+    return;
+  }
+
+  // Update skills list
+  plugin.skills = currentSkills;
+
+  // Update description with new count
+  plugin.description = updateSkillCount(plugin.description, currentSkills.length);
+
+  // Write updated marketplace.json
+  fs.writeFileSync(MARKETPLACE_FILE, JSON.stringify(marketplace, null, 2) + "\n");
+
+  // Report changes
+  const added = currentSkills.filter((s) => !existingSkills.includes(s));
+  const removed = existingSkills.filter((s) => !currentSkills.includes(s));
+
+  if (added.length) console.log(`Added: ${added.join(", ")}`);
+  if (removed.length) console.log(`Removed: ${removed.join(", ")}`);
+
+  console.log(`Updated marketplace.json (${currentSkills.length} skills)`);
+}
+
+main();

.github/workflows/sync-claude-plugin.yml

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+name: Sync Claude Plugin
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'skills/**'
+
+jobs:
+  sync:
+    runs-on: ubuntu-slim
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          persist-credentials: true
+
+      - name: Sync skills to marketplace.json
+        run: node .github/scripts/sync-marketplace.js
+
+      - name: Commit changes
+        uses: stefanzweifel/git-auto-commit-action@v7
+        with:
+          commit_message: "chore: sync marketplace.json with skills directory"
+          file_pattern: .claude-plugin/marketplace.json

.github/workflows/validate-skill.yml

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+name: Validate Agent Skill
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - "**/SKILL.md"
+  pull_request:
+    branches: [main]
+    paths:
+      - "**/SKILL.md"
+
+concurrency:
+  group: validate-skill-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  detect-changes:
+    runs-on: ubuntu-slim
+    if: github.event.pull_request.draft != true && github.actor != 'dependabot[bot]'
+    outputs:
+      skills: ${{ steps.changed-skills.outputs.skills }}
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Get changed skills
+        id: changed-skills
+        run: |
+          if [ "${{ github.event_name }}" = "pull_request" ]; then
+            BASE=${{ github.event.pull_request.base.sha }}
+            HEAD=${{ github.event.pull_request.head.sha }}
+          else
+            BASE=${{ github.event.before }}
+            HEAD=${{ github.event.after }}
+          fi
+
+          # Find changed SKILL.md files and extract skill directories
+          SKILLS=$(git diff --name-only $BASE $HEAD | \
+            grep 'SKILL.md$' | \
+            xargs -I {} dirname {} | \
+            sort -u | \
+            jq -R -s -c 'split("\n") | map(select(length > 0))')
+
+          echo "skills=$SKILLS" >> $GITHUB_OUTPUT
+          echo "Changed skills: $SKILLS"
+
+  validate:
+    needs: detect-changes
+    if: needs.detect-changes.outputs.skills != '[]'
+    runs-on: ubuntu-slim
+    strategy:
+      fail-fast: false
+      matrix:
+        skill: ${{ fromJson(needs.detect-changes.outputs.skills) }}
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - name: Validate ${{ matrix.skill }}
+        uses: Flash-Brew-Digital/validate-skill@v1
+        with:
+          path: ${{ matrix.skill }}