Cobalt Web image Dockerfile

Build and run image with

```
docker build -f web/Dockerfile -t cobalt-web .
docker run -e WEB_DEFAULT_API="https://real.api.endpoint" -e WEB_HOST="http://abc"  -e WEB_PLAUSIBLE_HOST="def" -p 800:80 cobalt-web
```

Currently, vite build still uses process.env env-vars at build time, so the docker container is not using those defined via placeholders in `runtime-config.js`

web/Dockerfile

@@ -0,0 +1,33 @@
+# syntax=docker/dockerfile:1
+
+
+# docker build -f web/Dockerfile -t cobalt-web .
+
+FROM node:20-alpine AS builder
+
+WORKDIR /repo
+
+RUN npm install -g pnpm
+
+# Copy monorepo into container
+COPY . .
+
+# Install all deps for monorepo
+RUN pnpm install --frozen-lockfile
+
+WORKDIR /repo/web
+RUN pnpm --filter ./web run build
+
+
+FROM nginx:alpine
+
+WORKDIR /usr/share/nginx/html
+COPY --from=builder /repo/web/build .
+
+COPY web/docker-entrypoint.sh /docker-entrypoint.sh
+RUN chmod +x /docker-entrypoint.sh
+
+EXPOSE 80
+
+ENTRYPOINT ["/docker-entrypoint.sh"]
+CMD ["nginx", "-g", "daemon off;"]

web/docker-entrypoint.sh

@@ -0,0 +1,12 @@
+#!/bin/sh
+set -e
+
+# Replace config placeholders with runtime values
+if [ -f "/usr/share/nginx/html/runtime-config.js" ]; then
+  envsubst '${WEB_HOST} ${WEB_PLAUSIBLE_HOST} ${WEB_DEFAULT_API}' \
+    < /usr/share/nginx/html/runtime-config.js \
+    > /usr/share/nginx/html/runtime-config.tmp.js && \
+    mv /usr/share/nginx/html/runtime-config.tmp.js /usr/share/nginx/html/runtime-config.js
+fi
+
+exec "$@"

web/pnpm-workspace.yaml

@@ -0,0 +1,4 @@
+packages:
+    - "api"
+    - "web"
+    - "packages/*"

web/static/runtime-config.js

@@ -0,0 +1,5 @@
+window.COBALT_CONFIG = {
+  WEB_HOST: "${WEB_HOST}",
+  WEB_PLAUSIBLE_HOST: "${WEB_PLAUSIBLE_HOST}",
+  WEB_DEFAULT_API: "${WEB_DEFAULT_API}"
+};