add kingmaker-style header, full pagination, and CI/CD deployment

- Hero carousel header with logo and photos matching kingmaker site
- Renamed "League Rank" to "ITC Rank"
- Full cursor-paginated standings scan with circular-cursor detection
  to handle BCP API's pagination bug at the end of results; incremental
  rendering shows results as each page arrives
- credentials:omit on all BCP fetches to prevent session cookie 500s
- GitLab CI pipeline: npm ci + vite build, rsync dist/ to
  /var/www/domains/gateway-gamers.net/rankings/ on push to main
- nginx config for rankings.gateway-gamers.net with CSP allowing
  connect-src to newprod-api.bestcoastpairings.com

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitlab-ci.yml

@@ -0,0 +1,25 @@
+stages:
+  - build
+  - deploy
+
+build:
+  stage: build
+  script:
+    - npm ci
+    - npm run build
+  artifacts:
+    paths:
+      - dist/
+    expire_in: 1 hour
+  only:
+    - main
+
+deploy:
+  stage: deploy
+  script:
+    - rsync -avz --delete dist/ /var/www/domains/gateway-gamers.net/rankings/
+  only:
+    - main
+  environment:
+    name: production
+    url: https://rankings.gateway-gamers.net