Add multi-stage Dockerfile, docker-compose, and fix insert conflict

Rebuild Dockerfile with 3 stages (CSS, uberjar, runtime) on port 3030.
Add docker-compose.yml loading .env. Fix insert-price! ON CONFLICT to
target (time_dk, price_area) matching the actual unique index.

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

Dockerfile

@@ -1,15 +1,22 @@
-# syntax = docker/dockerfile:1.2
-FROM clojure:openjdk-17 AS build
+FROM node:22-alpine AS css
+WORKDIR /app
+COPY package.json package-lock.json ./
+RUN npm ci
+COPY resources/css resources/css
+COPY src src
+RUN npx @tailwindcss/cli -i resources/css/input.css -o resources/public/css/output.css --minify
 
-WORKDIR /
-COPY . /
+FROM clojure:temurin-21-tools-deps-alpine AS build
+WORKDIR /app
+COPY deps.edn build.clj ./
+RUN clojure -P && clojure -P -T:build
+COPY . .
+COPY --from=css /app/resources/public/css/output.css resources/public/css/output.css
+RUN clojure -T:build all
 
-RUN clj -Sforce -T:build all
-
-FROM azul/zulu-openjdk-alpine:17
-
-COPY --from=build /target/elprice-standalone.jar /elprice/elprice-standalone.jar
-
-EXPOSE $PORT
-
-ENTRYPOINT exec java $JAVA_OPTS -jar /elprice/elprice-standalone.jar
+FROM eclipse-temurin:21-jre-alpine
+WORKDIR /app
+COPY --from=build /app/target/elprice-standalone.jar app.jar
+EXPOSE 3030
+ENV PORT=3030
+ENTRYPOINT ["java", "-jar", "app.jar"]