fix: resolve peer dependency conflict in Docker build

Use --legacy-peer-deps for npm ci to handle @types/react v19 vs
@cypress/react18 peer dependency conflict. Also fixed FROM AS casing.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Dockerfile

@@ -1,10 +1,10 @@
-FROM node:18-alpine as builder
+FROM node:18-alpine AS builder
 
 WORKDIR /app
 
 COPY package*.json ./
 
-RUN npm ci
+RUN npm ci --legacy-peer-deps
 
 COPY . .