chore: add CI workflow to validate plugin manifest on every PR

.claude-plugin/marketplace.json

@@ -1,5 +1,7 @@
 {
+  "$schema": "https://json.schemastore.org/claude-code-marketplace.json",
   "name": "gringolito",
+  "description": "Plugins by Filipe Utzig",
   "owner": {
     "name": "Filipe Utzig",
     "email": "filipe@gringolito.com"

.claude-plugin/plugin.json

@@ -1,4 +1,5 @@
 {
+  "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "github-backlog-management",
   "description": "GitHub-native backlog automation. Manage Issues + Projects v2 with AI-enforced INVEST quality, dependency tracking, and one-command execution.",
   "version": "0.2.0",

.github/workflows/ci.yaml

@@ -0,0 +1,30 @@
+name: CI
+
+on:
+  pull_request:
+    branches:
+      - "*"
+  push:
+    branches:
+      - master
+
+permissions:
+  contents: read
+
+jobs:
+  validate-plugin:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Install Claude Code
+        run: npm install -g @anthropic-ai/claude-code
+
+      - name: Check Claude Code installed version
+        run: claude --version
+
+      - name: Validate marketplace manifest
+        run: claude plugin validate .claude-plugin/marketplace.json
+
+      - name: Validate plugin manifest
+        run: claude plugin validate .claude-plugin/plugin.json