chore: reproducible pipeline with dev containers (#10305)

# Which Problems Are Solved

- The previous monorepo in monorepo structure for the login app and its
related packages was fragmented, complicated and buggy.
- The process for building and testing the login container was
inconsistent between local development and CI.
- Lack of clear documentation as well as easy and reliable ways for
non-frontend developers to reproduce and fix failing PR checks locally.

# How the Problems Are Solved

- Consolidated the login app and its related npm packages by moving the
main package to `apps/login/apps/login` and merging
`apps/login/packages/integration` and `apps/login/packages/acceptance`
into the main `apps/login` package.
- Migrated from Docker Compose-based test setups to dev container-based
setups, adding support for multiple dev container configurations:
  - `.devcontainer/base`
  - `.devcontainer/turbo-lint-unit`
  - `.devcontainer/turbo-lint-unit-debug`
  - `.devcontainer/login-integration`
  - `.devcontainer/login-integration-debug`
- Added npm scripts to run the new dev container setups, enabling exact
reproduction of GitHub PR checks locally, and updated the pipeline to
use these containers.
- Cleaned up Dockerfiles and docker-bake.hcl files to only build the
production image for the login app.
- Cleaned up compose files to focus on dev environments in dev
containers.
- Updated `CONTRIBUTING.md` with guidance on running and debugging PR
checks locally using the new dev container approach.
- Introduced separate Dockerfiles for the login app to distinguish
between using published client packages and building clients from local
protos.
- Ensured the login container is always built in the pipeline for use in
integration and acceptance tests.
- Updated Makefile and GitHub Actions workflows to use
`--frozen-lockfile` for installing pnpm packages, ensuring reproducible
installs.
- Disabled GitHub release creation by the changeset action.
- Refactored the `/build` directory structure for clarity and
maintainability.
- Added a `clean` command to `docks/package.json`.
- Experimentally added `knip` to the `zitadel-client` package for
improved linting of dependencies and exports.

# Additional Changes

- Fixed Makefile commands for consistency and reliability.
- Improved the structure and clarity of the `/build` directory to
support seamless integration of the login build.
- Enhanced documentation and developer experience for running and
debugging CI checks locally.

# Additional Context

- See updated `CONTRIBUTING.md` for new local development and debugging
instructions.
- These changes are a prerequisite for further improvements to the CI
pipeline and local development workflow.
- Closes #10276

apps/login/Dockerfile

@@ -0,0 +1,36 @@
+FROM node:20-alpine AS base
+
+FROM base AS build
+ENV PNPM_HOME="/pnpm"
+ENV PATH="$PNPM_HOME:$PATH"
+RUN corepack enable && COREPACK_ENABLE_DOWNLOAD_PROMPT=0 corepack prepare pnpm@9.1.2 --activate && \
+    apk update && apk add --no-cache && \
+    rm -rf /var/cache/apk/*
+WORKDIR /app
+COPY pnpm-lock.yaml ./
+RUN --mount=type=cache,id=pnpm,target=/root/.local/share/pnpm/store pnpm fetch --frozen-lockfile
+COPY package.json ./
+RUN --mount=type=cache,id=pnpm,target=/root/.local/share/pnpm/store pnpm install --frozen-lockfile --prod
+COPY . .
+RUN pnpm build:login:standalone
+
+FROM scratch AS build-out
+COPY --from=build /app/.next/standalone /
+COPY --from=build /app/.next/static /.next/static
+COPY --from=build /app/public /public
+
+FROM base AS login-standalone
+WORKDIR /runtime
+RUN addgroup --system --gid 1001 nodejs && \
+    adduser --system --uid 1001 nextjs
+# If /.env-file/.env is mounted into the container, its variables are made available to the server before it starts up.
+RUN mkdir -p /.env-file && touch /.env-file/.env && chown -R nextjs:nodejs /.env-file
+COPY ./scripts/ ./
+COPY --chown=nextjs:nodejs --from=build-out / ./
+USER nextjs
+ENV HOSTNAME="0.0.0.0"
+ENV PORT=3000
+# TODO: Check healthy, not ready
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+CMD ["/bin/sh", "-c", "node ./healthcheck.js http://localhost:${PORT}/ui/v2/login/healthy"]
+ENTRYPOINT ["./entrypoint.sh"]