Add multi-mode HTML, Docker, Helm chart, and deploy script

- Add shop-mode.html and project-mode.html for separate calculation
modes - Refactor index.html as a landing page for mode selection - Add
Dockerfile with optimized nginx config and healthcheck - Add
.dockerignore for cleaner Docker builds - Add deploy.sh for
Helm/Kubernetes deployment automation - Add helm-chart/ with
values.yaml, Chart.yaml, templates, and documentation - Update README.md
with full instructions, features, and CI/CD examples

.dockerignore

@@ -0,0 +1,38 @@
+# Git
+.git
+.gitignore
+.gitea
+
+# Helm
+helm-chart/
+*.md
+
+# CI/CD
+.gitlab-ci.yml
+.github/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Backup files
+*.bak
+*.tmp
+*.orig
+
+# Documentation
+README.md
+LICENSE
+docs/
+
+# Node modules (if any)
+node_modules/
+package-lock.json
+yarn.lock