chore: improve docker compose template, tests and docs (#11593)

Replaces the single-file `docker-compose.yaml` quickstart with a
production-aware, Traefik-based compose pack in `deploy/compose/`. The
pack covers the full arc from a 2-minute localhost quickstart to a
hardened homelab or semi-production deployment.

### What's in the pack

**Stack**: Traefik (proxy) → ZITADEL API (Go `:8080`) + ZITADEL Login
(Next.js `:3000`) → PostgreSQL

All HTTP/gRPC routing is handled by Traefik via Docker labels — no
manual proxy config needed. The Login V2 UI is enabled by default. Login
URLs are derived automatically from `ZITADEL_DOMAIN`,
`ZITADEL_EXTERNALPORT`, and `ZITADEL_PUBLIC_SCHEME` — no separate URL
variables needed.

**Compose files**

| File | Purpose |
|------|---------|
| `docker-compose.yml` | Base stack — works standalone. Uses explicit
`name: zitadel` network for reliable Traefik service discovery. |
| `docker-compose.mode-letsencrypt.yml` | TLS overlay: ACME HTTP
challenge |
| `docker-compose.mode-external-tls.yml` | TLS overlay: upstream LB/CDN
terminates TLS. Uses `forwardedHeaders.trustedIPs` (configurable via
`TRAEFIK_TRUSTED_IPS`) instead of `insecure=true`. |
| `docker-compose.mode-local-tls.yml` | TLS overlay: self-signed certs
for LAN |
| `docker-compose.prodlike.yml` | Splits init / setup / start for
controlled upgrades |
| `docker-compose.test.yml` | CI overlay: swaps images to locally-built
`:local` tags |

**Optional profiles**: `cache` (Redis), `observability` (OpenTelemetry
Collector)

### Build infra

- New `@zitadel/api:pack` and `@zitadel/login:pack` Nx targets build
local Docker images (`zitadel/zitadel:local`,
`zitadel/zitadel-login:local`) for use in CI and local testing
- `apps/api/Dockerfile` now accepts a `BINARY` build arg so local and
release builds share the same image

### Testing

- New `@zitadel/compose` Nx project with targets: `test-config`
(validates all overlay combinations using `--quiet`), `test-run` (starts
full stack with local images), `test-e2e` (Playwright wiring + protocol
matrix tests through Traefik), `test-full` (end-to-end: build → start →
test → teardown), `stop`
- **`@zitadel/compose` is explicitly excluded from `nx affected` in CI
for now** — the full stack smoke test requires a Docker daemon and
significant resources. The intent is to add a dedicated
`compose_smoke_test` CI job in a follow-up. The targets can be run
locally with `pnpm nx run @zitadel/compose:test-full`.

### Documentation

- **`compose.mdx`**: Complete rewrite with a staged structure (Stage 1
Quickstart → Stage 2 Homelab → Stage 3 Beyond Compose). Documents TLS
modes, profiles, secrets hardening, ExternalDomain/Port/Secure
invariant, upgrades, and the path to Kubernetes
- **New `requirements.mdx`**: Lists supported PostgreSQL versions
(14–18), Redis (standalone), Docker Compose v2.x, and reverse proxy h2c
requirements
- **`reverse_proxy.mdx`**: Added intro covering h2c requirements, TLS
modes table, and Login UI routing split
- **`troubleshooting.mdx`**: New sections for container restarts on
upgrade, FIRSTINSTANCE env vars not taking effect, and diagnosing
unhealthy containers
- **`caddy/index.mdx`**: Known issue and workaround for the `TE:
trailers` header hang
- Removed the old
`apps/docs/content/self-hosting/deploy/docker-compose.yaml` embedded in
the docs

### Breaking change

The old `apps/docs/content/self-hosting/deploy/docker-compose.yaml` file
is deleted. The getting-started docs page
(`/self-hosting/deploy/compose`) now points to the new pack via a `curl
| tar` download command.

---

### Checklist

- [x] `deploy/compose/` smoke test passes end-to-end locally (`pnpm nx
run @zitadel/compose:test-full`)
- [x] Docs build passes (`pnpm nx run @zitadel/docs:build`)
- [ ] Follow-up issue created to add `compose_smoke_test` CI job

---------

Co-authored-by: Mridang Agarwalla <[email protected]>

.github/copilot-instructions.md

@@ -14,6 +14,7 @@ You are working in the ZITADEL monorepo. This codebase uses specific conventions
 - `proto/AGENTS.md`: API schema and generation guidance.
 - `packages/AGENTS.md`: Shared client/proto package workflows.
 - `tests/functional-ui/AGENTS.md`: Cypress functional UI test workflows.
+- `deploy/compose/AGENTS.md`: Docker Compose deployment invariants, file conventions, and rejected alternatives.
 
 ## Behavior
 - Before Go-related work, inspect `go.mod` for required Go version/toolchain.
@@ -21,3 +22,4 @@ You are working in the ZITADEL monorepo. This codebase uses specific conventions
 - For backend changes, note we are in transition: relational data is becoming the system of record, while event writes are still required for history/audit.
 - Respect terminology defined in the `Technical Glossary` section of `AGENTS.md` when generating UI text or documentation.
 - Distinguish between `apps/login` (Next.js) and `console` (Angular) when suggesting frontend code.
+- For deployment-related work, consult the directory-specific agents files (e.g., `deploy/compose/AGENTS.md`) for invariants, file conventions, and rejected alternatives.

.github/semantic.yml

@@ -50,6 +50,8 @@ scopes:
   # API layer
   - grpc
   - proto
+  # Deployment
+  - deploy
   # Cross-cutting
   - build
   - ci