migrate to hantim org and consolidate deploy secret name

- Update all references from timothykim/ to hantim/ org
- Rename DEPLOY_KEY to DEPLOY_SSH_KEY everywhere
- Update README to reference org-level secrets

scripts/new-app.sh

@@ -26,7 +26,7 @@ mkdir -p "$REPO_ROOT/docker/$APP"
 cat > "$REPO_ROOT/docker/$APP/compose.yml" <<EOF
 services:
   app:
-    image: git.timothykim.net/timothykim/$APP:latest
+    image: git.timothykim.net/hantim/$APP:latest
     restart: unless-stopped
     networks:
       - shared
@@ -54,7 +54,7 @@ jobs:
       - name: Deploy via SSH
         run: |
           mkdir -p ~/.ssh
-          echo "${{ secrets.DEPLOY_KEY }}" > ~/.ssh/deploy_key
+          echo "${{ secrets.DEPLOY_SSH_KEY }}" > ~/.ssh/deploy_key
           chmod 600 ~/.ssh/deploy_key
           ssh -o StrictHostKeyChecking=accept-new -i ~/.ssh/deploy_key deploy@${{ secrets.DEPLOY_HOST }} deploy-APP_PLACEHOLDER
 OUTER