chore: adapt Dockerfile/compose for standalone server repo

- Dockerfile no longer bakes in a Flutter web build (this repo has no
  client/ dir); the web bundle is mounted at runtime instead.
- docker-compose.yml: web bundle mount path configurable via
  WEB_CLIENT_BUILD_PATH, defaults to a sibling KC-APP checkout.
- README: point to the KC-APP client repo for clients.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Dockerfile

@@ -1,9 +1,8 @@
 # syntax=docker/dockerfile:1
 #
-# The Flutter web bundle is built on the HOST (it needs a ~2.8 GB SDK image
-# otherwise). Before `docker compose build`, run:
-#     (cd client/app && flutter build web --release)
-# This Dockerfile just copies client/app/build/web into the runtime image.
+# Server-only image (this repo has no Flutter client). The web client is
+# built in the KC-APP client repo and its `build/web` output is mounted
+# into the container at runtime via WEB_CLIENT_DIR (see docker-compose.yml).
 
 # --- 1. Backend build ---------------------------------------------------------
 FROM node:20-bookworm-slim AS api-build
@@ -13,9 +12,9 @@ WORKDIR /src
 # openssl-1.1.x, which then fails to load in the runtime stage (openssl 3.0.x).
 RUN apt-get update && apt-get install -y --no-install-recommends openssl \
   && rm -rf /var/lib/apt/lists/*
-COPY backend/package.json backend/package-lock.json ./
+COPY package.json package-lock.json ./
 RUN npm ci
-COPY backend/ ./
+COPY . .
 RUN npx prisma generate && npm run build
 
 # --- 2. Runtime -------------------------------------------------------------
@@ -28,9 +27,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends openssl \
 COPY --from=api-build /src/node_modules ./node_modules
 COPY --from=api-build /src/dist ./dist
 COPY --from=api-build /src/prisma ./prisma
-# Pre-built Flutter web bundle from the host; app.module reads WEB_CLIENT_DIR.
-COPY client/app/build/web ./web
-ENV WEB_CLIENT_DIR=/app/web
+# Web client bundle is bind-mounted at runtime, not baked into the image;
+# app.module reads WEB_CLIENT_DIR. See docker-compose.yml.
 EXPOSE 3000
 # Apply pending migrations, then boot.
 CMD ["sh", "-c", "npx prisma migrate deploy && node dist/main.js"]