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

helm-chart/.helmignore

@@ -0,0 +1,26 @@
+# Patterns to ignore when building packages.
+# This supports shell glob matching, relative path matching, and
+# negation (prefixed with !). Only one pattern per line.
+.DS_Store
+# Common VCS dirs
+.git/
+.gitignore
+.bzr/
+.bzrignore
+.hg/
+.hgignore
+.svn/
+# Common backup files
+*.swp
+*.bak
+*.tmp
+*.orig
+*~
+# Various IDEs
+.project
+.idea/
+*.tmproj
+.vscode/
+# Custom
+README.md
+.helmignore