feat: diffity as a hosted multi-user server

.dockerignore

@@ -0,0 +1,11 @@
+**/node_modules
+**/dist
+**/*.tsbuildinfo
+**/.react-router
+.git
+.diffity
+.claude
+.bin
+plans
+tmp
+snapshot-*

Dockerfile

@@ -0,0 +1,51 @@
+# The hosted diffity server (packages/server). Build from the repository root:
+#   docker build -t diffity-server .
+
+FROM node:24-slim AS build
+WORKDIR /src
+COPY package.json package-lock.json ./
+COPY packages/api/package.json packages/api/
+COPY packages/cli/package.json packages/cli/
+COPY packages/git/package.json packages/git/
+COPY packages/github/package.json packages/github/
+COPY packages/parser/package.json packages/parser/
+COPY packages/server/package.json packages/server/
+COPY packages/ui/package.json packages/ui/
+RUN npm ci
+COPY . .
+RUN npm run build
+
+FROM node:24-slim AS deps
+WORKDIR /app
+COPY package.json package-lock.json ./
+COPY packages/api/package.json packages/api/
+COPY packages/cli/package.json packages/cli/
+COPY packages/git/package.json packages/git/
+COPY packages/github/package.json packages/github/
+COPY packages/parser/package.json packages/parser/
+COPY packages/server/package.json packages/server/
+COPY packages/ui/package.json packages/ui/
+# The workspace packages are bundled into dist; only the server's npm dependencies are installed.
+RUN npm ci --omit=dev --workspace @diffity/server --include-workspace-root=false --ignore-scripts
+
+FROM node:24-slim
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends git ca-certificates \
+  && rm -rf /var/lib/apt/lists/* \
+  && useradd --system --uid 10001 --home-dir /data --shell /usr/sbin/nologin diffity \
+  && mkdir -p /data \
+  && chown diffity:diffity /data
+WORKDIR /app
+COPY --from=deps /app/node_modules ./node_modules
+COPY --from=build /src/packages/server/package.json ./package.json
+COPY --from=build /src/packages/server/dist ./dist
+ENV NODE_ENV=production \
+  DIFFITY_DATA_DIR=/data \
+  DIFFITY_BIND=0.0.0.0 \
+  PORT=5390
+USER diffity
+VOLUME /data
+EXPOSE 5390
+HEALTHCHECK --interval=30s --timeout=5s --start-period=10s \
+  CMD ["node", "-e", "fetch('http://127.0.0.1:' + (process.env.PORT || 5390) + '/healthz').then(r => process.exit(r.ok ? 0 : 1), () => process.exit(1))"]
+CMD ["node", "dist/index.js"]