Fix: Update Docker config to use pnpm instead of npm

- Switched from npm ci to pnpm install --frozen-lockfile
- Added corepack enable for pnpm support
- Added .dockerignore for cleaner builds

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker-compose.yml

@@ -1,7 +1,6 @@
-version: '3.8'
-
 services:
   portfolio:
+    container_name: portfolio-website
     build:
       context: .
       dockerfile: Dockerfile
@@ -14,3 +13,9 @@ services:
       - NEXT_PUBLIC_GA_TRACKING_ID=${NEXT_PUBLIC_GA_TRACKING_ID}
       - NEXT_PUBLIC_SITE_URL=${NEXT_PUBLIC_SITE_URL}
     restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "wget", "-q", "--spider", "http://localhost:3000"]
+      interval: 30s
+      timeout: 10s
+      retries: 3
+      start_period: 40s