Add CODEOWNERS file and create GitHub Actions workflow for automatic deployment to Vercel

Author: mathieulrl

.github/CODEOWNERS

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+# Require PRs modifying any file to be approved by these users
+* @mathieulrl @thibaultlangloisberthelot

.github/workflows/push-to-vercel.yml

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+name: Push to Fork (kryptosphere-dev)
+
+on:
+  push:
+    branches:
+      - vercel
+
+jobs:
+  sync-to-fork:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Set up SSH
+        run: |
+          mkdir -p ~/.ssh
+          echo "${{ secrets.DEPLOY_SSH_KEY }}" > ~/.ssh/id_ed25519
+          chmod 600 ~/.ssh/id_ed25519
+          ssh-keyscan github.com >> ~/.ssh/known_hosts
+
+      - name: Set Git config
+        run: |
+          git config --global user.name "GitHub Action"
+          git config --global user.email "actions@github.com"
+
+      - name: Make change (example)
+        run: |
+          echo "Last pushed at $(date -u)" > version.txt
+          git add version.txt
+
+      - name: Remove workflows from commit
+        run: |
+          git restore --staged .github/workflows || true
+          git restore .github/workflows || true
+
+      - name: Commit if needed
+        run: |
+          git diff --cached --quiet || git commit -m "Update version file at $(date -u)"
+
+      - name: Push to kryptosphere-dev
+        run: |
+          git remote add fork git@github.com:kryptosphere-dev/kryptosphere-api.git
+          git push fork vercel --force