fix(docker): add --legacy-peer-deps to npm ci for svelte-markdown@0.4.1 compat

svelte-markdown@0.4.1 declares peer dependency svelte@^4.0.0, but the
project uses svelte@^5.43.8. In clean Docker builds, npm ci strictly
validates peer deps and fails. Adding --legacy-peer-deps works around
the incompatibility until svelte-markdown supports Svelte 5.

docker-compose.e2e.yml

@@ -69,7 +69,7 @@ services:
       - /tmp/playwright-report:/workspace/frontend/playwright-report
     command: >
       sh -c "
-        npm ci &&
+        npm ci --legacy-peer-deps &&
         npx playwright install chromium &&
         npx playwright test
       "

docker/all-in-one.Dockerfile

@@ -16,7 +16,7 @@ WORKDIR /app/frontend
 
 # Install deps (layer cache when package.json unchanged)
 COPY frontend/package.json frontend/package-lock.json* ./
-RUN npm ci --prefer-offline --no-audit --no-fund
+RUN npm ci --prefer-offline --no-audit --no-fund --legacy-peer-deps
 
 # Build frontend
 COPY frontend/ ./

docker/frontend.Dockerfile

@@ -13,7 +13,7 @@ FROM node:20-alpine AS build
 WORKDIR /app/frontend
 
 COPY frontend/package*.json ./
-RUN npm ci
+RUN npm ci --legacy-peer-deps
 
 COPY frontend/ ./
 RUN npm run build