Route social link preview fetches through Cloudflare worker (#18)

- add a social-link-preview Cloudflare Worker that fetches page HTML, extracts metadata, and returns guideline results
- rework the social link preview frontend to call the worker API and render the returned reports
- document the new worker and hook it into the deployment workflow

------
[Codex Task](https://chatgpt.com/codex/tasks/task_e_6915ea5572788325b434762c9a96d607)

Author: rodrigogiraoserrao

.github/workflows/deploy-cloudflare-workers.yml

@@ -16,6 +16,7 @@ jobs:
       pull-requests: read
     outputs:
       gumroad_products: ${{ steps.filter.outputs.gumroad-products }}
+      social_link_preview: ${{ steps.filter.outputs.social-link-preview }}
       # If I add more filters below, I need to “export them” here.
     steps:
     - uses: actions/checkout@v4
@@ -27,6 +28,8 @@ jobs:
         filters: |
           gumroad-products:
             - 'cloudflare-workers/gumroad-products/**'
+          social-link-preview:
+            - 'cloudflare-workers/social-link-preview/**'
         # I can add more filters here and access them separately.
 
   deploy-gumroad-products:
@@ -53,3 +56,28 @@ jobs:
           CLOUDFLARE_ACCOUNT_ID: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
         run: |
           wrangler deploy --env production
+
+  deploy-social-link-preview:
+    name: Deploy Social Link Preview Worker
+    runs-on: ubuntu-latest
+    needs: changes
+    if: ${{ github.event_name == 'workflow_dispatch' || needs.changes.outputs.social_link_preview == 'true' }}
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Install Wrangler
+        run: npm install -g wrangler
+
+      - name: Deploy to Cloudflare Workers
+        working-directory: cloudflare-workers/social-link-preview
+        env:
+          CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
+          CLOUDFLARE_ACCOUNT_ID: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
+        run: |
+          wrangler deploy --env production

cloudflare-workers/README.md

@@ -14,6 +14,10 @@ Each worker lives in its own subdirectory with:
 - **Location**: `cloudflare-workers/gumroad-products/`
 - **Purpose**: Fetch products from a Gumroad user profile page
 
+### social-link-preview
+- **Location**: `cloudflare-workers/social-link-preview/`
+- **Purpose**: Fetch a URL server-side, extract metadata, and return link preview reports for the frontend tool
+
 ## Setup Instructions
 
 ### 1. Install Wrangler CLI (Optional - for local development)