feat: adds flag validation workflows

Adds a workflow to validate feature flag changes against the base
branch and a remote manifest. This ensures consistency and
correctness of flag configurations.

Signed-off-by: Kris Coleman <kriscodeman@gmail.com>

Author: kriscoleman

.github/workflows/pr-check.yaml

@@ -20,8 +20,8 @@ jobs:
       - name: Setup Node
         uses: actions/setup-node@v4
         with:
-          node-version-file: '.nvmrc'
-          cache: 'npm'
+          node-version-file: ".nvmrc"
+          cache: "npm"
 
       - name: Restore cache
         uses: actions/cache@v4
@@ -40,9 +40,38 @@ jobs:
         if: always()
         uses: ctrf-io/github-test-reporter@v1
         with:
-          report-path: './ctrf/*.json'
+          report-path: "./ctrf/*.json"
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Build with Next.js
-        run: npm run build
+        run: npm run build
+
+  validate-flags:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0 # Required for git branch comparison
+
+      - name: Compare against base branch
+        uses: open-feature/action@v0.0.2
+        with:
+          manifest: "flags.json"
+          # Automatically compares against PR base branch (main)
+      - name: Check FLAGD_STUDIO_TOKEN secret
+        run: |
+          if [ -z "${{ secrets.FLAGD_STUDIO_TOKEN }}" ]; then
+            echo "WARNING: FLAGD_STUDIO_TOKEN is not set. Remote manifest comparison may fail."
+          fi
+
+      - name: Compare against remote manifest
+        uses: open-feature/action@v0.0.2
+        with:
+          manifest: "flags.json"
+          against: "https://flagd-studio.onrender.com/api"
+          auth-token: ${{ secrets.FLAGD_STUDIO_TOKEN }}