feat(ui): avatar crop modal, health endpoint, leaner Dockerfile

- Add AvatarCropModal.svelte using cropperjs v1: 1:1 crop, 400×400 output,
  JPEG/WebP output, dark glassmorphic UI
- Rewrite profile page avatar upload to use presigned PUT flow (POST→PUT→PATCH)
  instead of sending raw FormData directly; crop modal opens on file select
- Add GET /health → {status:ok} for Docker healthcheck
- Simplify Dockerfile: drop runtime npm ci (adapter-node bundles all deps)
- Fix docker-compose UI healthcheck: /health route, 127.0.0.1 to avoid
  IPv6 localhost resolution failure in alpine busybox wget

ui/Dockerfile

@@ -8,16 +8,11 @@ COPY . .
 RUN npm run build
 
 # ── Runtime image ──────────────────────────────────────────────────────────────
+# adapter-node bundles all dependencies into build/ — no npm install needed.
 FROM node:22-alpine
 WORKDIR /app
 
-# adapter-node produces a standalone build/
 COPY --from=builder /app/build ./build
-COPY --from=builder /app/package.json ./
-COPY --from=builder /app/package-lock.json ./
-
-# Install production dependencies (e.g. marked) that are imported at runtime
-RUN npm ci --omit=dev
 
 ENV NODE_ENV=production
 ENV PORT=3000
@@ -25,3 +20,4 @@ ENV HOST=0.0.0.0
 
 EXPOSE $PORT
 CMD ["node", "build"]
+