feat(deploy): containerize api + web for single-host docker-compose

- apps/api/Dockerfile: multi-stage build, runs prisma migrate deploy on
  boot. Workspace package.json "main/exports" rewritten to dist so Node
  ESM resolves compiled JS at runtime.
- apps/web/Dockerfile + nginx.conf: static build served by nginx with
  SPA fallback, gzip, cache-bust on hashed assets, and /api reverse
  proxy to the internal api service.
- docker-compose.yml: production-oriented stack — api (SQLite on a
  named volume), web (exposes WEB_PORT), redis (for the upcoming
  worker). Postgres dropped since schema still targets SQLite.
- .dockerignore: keep build context lean.
- ci: add docker job gated on push-to-main that builds and pushes both
  images to ${{ vars.REGISTRY_URL }} using ${{ secrets.REGISTRY_TOKEN }}.
  Tags :latest + :${github.sha}.

apps/web/Dockerfile

@@ -0,0 +1,31 @@
+# syntax=docker/dockerfile:1.7
+
+# ---------- build ----------
+FROM node:22-alpine AS build
+RUN corepack enable && corepack prepare pnpm@10.33.0 --activate
+WORKDIR /repo
+
+COPY pnpm-workspace.yaml pnpm-lock.yaml package.json ./
+COPY apps/api/package.json        ./apps/api/
+COPY apps/web/package.json        ./apps/web/
+COPY apps/e2e/package.json        ./apps/e2e/
+COPY packages/db/package.json     ./packages/db/
+COPY packages/shared/package.json ./packages/shared/
+COPY packages/ui/package.json     ./packages/ui/
+COPY packages/config/package.json ./packages/config/
+RUN pnpm install --frozen-lockfile
+
+COPY . .
+
+RUN pnpm -C packages/shared build \
+ && pnpm -C apps/web build
+
+# ---------- runtime ----------
+FROM nginx:alpine
+RUN apk add --no-cache wget
+COPY apps/web/nginx.conf /etc/nginx/conf.d/default.conf
+COPY --from=build /repo/apps/web/dist /usr/share/nginx/html
+
+EXPOSE 80
+HEALTHCHECK --interval=30s --timeout=3s --start-period=10s --retries=3 \
+  CMD wget -qO- http://localhost/ || exit 1