devops: CI/CD- Add main-branch EC2 auto deploy workflow

.github/workflows/deploy-main.yml

@@ -0,0 +1,61 @@
+name: Deploy Main To EC2
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'backend/**'
+      - 'web/**'
+      - '.github/workflows/deploy-main.yml'
+
+concurrency:
+  group: deploy-main-ec2
+  cancel-in-progress: true
+
+jobs:
+  deploy:
+    name: Deploy Backend + Frontend
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Deploy over SSH
+        uses: appleboy/ssh-action@v1.2.0
+        with:
+          host: ${{ secrets.SERVER_HOST }}
+          username: ${{ secrets.SERVER_USER }}
+          key: ${{ secrets.SERVER_SSH_KEY }}
+          port: ${{ secrets.SERVER_PORT }}
+          script_stop: true
+          script: |
+            set -euo pipefail
+
+            cd "${{ secrets.SERVER_PATH }}"
+
+            git fetch origin
+            git checkout main
+            git pull --ff-only origin main
+
+            cd backend
+            if [ -f package-lock.json ]; then
+              npm ci --omit=dev --no-audit --no-fund || npm install --omit=dev --no-audit --no-fund
+            else
+              npm install --omit=dev --no-audit --no-fund
+            fi
+
+            pm2 restart neph-backend || pm2 start src/server.js --name neph-backend
+
+            cd ../web
+            if [ -f package-lock.json ]; then
+              npm ci --no-audit --no-fund || npm install --no-audit --no-fund
+            else
+              npm install --no-audit --no-fund
+            fi
+
+            npm run build
+            pm2 restart neph-web || pm2 start npm --name neph-web -- start -- -p 3001
+
+            pm2 save
+
+            curl -fsS http://127.0.0.1:3000/health >/dev/null
+            curl -fsSI http://127.0.0.1:3001 >/dev/null