Phase 1: accounts and sessions

Implements PLAN.md Phase 1. A client can now register, log in, manage its
devices and set its profile; an operator can create accounts and flip the
runtime switches. There are still no rooms and no real /sync.

userapi: accounts, argon2id passwords in PHC format, devices, access and
refresh tokens stored as SHA-256 hashes, account data and the admin flag.
Its storage interface is storage.UserStore, implemented once in sqlstore
with `?` placeholders; the postgres driver supplies a rebind function and
unique-violation recognition rather than keeping a second copy of thirty
statements. Timestamps in these tables are int64 milliseconds, the unit the
Client-Server API uses on the wire.

Client-Server API: register (user-interactive auth with m.login.dummy and
optional registration tokens), register/available, token validity, login
with m.login.password, logout, logout/all, refresh, account/whoami,
capabilities, devices/* with password-gated deletion, profile/*, global and
per-room account data.

GET /sync is a deliberate placeholder: it answers a valid token with an
empty but well-formed response and refuses a revoked one. Phase 1 has no
rooms, so that is the whole truth, and it is what makes session revocation
observable. Phase 4 replaces it with the syncapi.

Auth middleware resolves a bearer token (header or the legacy query
parameter) to a device and user, answering an expired token with the soft
logout the spec asks for. Rate limiting is a token bucket per endpoint class
keyed on the client address, returning M_LIMIT_EXCEEDED with retry_after_ms.

adminapi v1 under /_warp/admin/v1: admin-only auth via a normal Matrix
token, GET/PUT /federation and /registration driving internal/settings and
reporting a config-pinned switch as a 409, GET/POST /users, GET /stats.

warp create-account [--admin] creates the first account straight in the
database, so a new install with registration off has a way in.

Complement is wired up for the federation=off profile: an image meeting its
contract, an entrypoint that configures Warp entirely from WARP_*
variables, and a runner that builds, clones and executes the target set
(TestRegistration, TestLogin, TestDeviceManagement). It has not been run
yet -- there is no container runtime on the development machine -- so the
three tests' assertions were read from the Complement sources and pinned as
httptest tests instead, and CI gained a job that runs the real thing.

Also fixes a .gitignore bug from Phase 0: the unanchored `warp` pattern,
meant for the built binary, also matched the directory server/cmd/warp and
silently excluded the entire command package from the repository. The
binary patterns are now anchored to the repository root, and cmd/warp is
committed for the first time.

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

server/test/complement/README.md

@@ -1,13 +1,67 @@
 # Complement
 
 [Complement](https://github.com/matrix-org/complement) is the official
-Matrix integration suite and the project's primary progress metric.
+Matrix integration suite and this project's primary progress metric
+(PLAN.md section 9). It runs one container per homeserver per test and
+drives it over the real HTTP API.
 
-It is wired up in Phase 1, once registration and login exist — before that
-there is nothing for it to test. Two profiles are planned, per PLAN.md
-section 9: `federation=off` (Client-Server tests only) and
-`federation=on`.
+```sh
+make complement                          # the current target set
+bash run.sh TestLogin                    # one test
+COMPLEMENT_DEBUG=1 make complement       # with the container logs
+```
 
-What will live here: the Dockerfile Complement boots, the image entrypoint
-that generates a signing key and a config per test homeserver, and the
-list of tests expected to pass.
+Needs Docker. [run.sh](run.sh) builds the image, clones Complement into
+`.complement/` at the repository root (git-ignored) and runs the subset for
+the phases that are done.
+
+## Files
+
+| | |
+|---|---|
+| [Dockerfile](Dockerfile) | the homeserver image, built from the repository root |
+| [entrypoint.sh](entrypoint.sh) | the deployment, entirely `WARP_*` environment variables |
+| [run.sh](run.sh) | build, clone, run |
+
+## Profiles
+
+**`federation=off`** — what runs today. Only the Client-Server tests;
+`WARP_FEDERATION_ENABLED=false`, port 8448 exposed but unserved.
+
+**`federation=on`** — Phase 5. It needs a TLS listener on 8448 with a
+certificate signed by the CA that Complement mounts at `/complement/ca`,
+which is the first thing to add here when federation lands.
+
+## The test set
+
+`COMPLEMENT_TESTS` in `run.sh` lists what is expected to pass. Phase 1:
+
+- `TestRegistration`
+- `TestLogin`
+- `TestDeviceManagement`
+
+Extend it as each phase lands rather than switching to the whole suite: a
+pass count that drops because a later phase is missing is noise, not
+information.
+
+Two notes on the environment, both in `entrypoint.sh`:
+
+- **Rate limiting is off.** The whole suite comes from the one address the
+  test runner has, so the limiter would spend the run returning
+  `M_LIMIT_EXCEEDED` and tell us nothing about the server. Synapse's own
+  Complement image does the same.
+- **Registration is on**, because the tests create their own users.
+
+## Tests that need later phases
+
+Some subtests of the three above reach for endpoints that are not Phase 1
+work. `TestDeviceManagement` calls `/sync` after creating a session, and
+`TestLogout` checks that a revoked token cannot sync. Phase 1 answers
+`/sync` with an empty but well-formed response for exactly that reason —
+there are no rooms yet, so an empty sync is the complete truth, and it makes
+token revocation observable. Phase 4 replaces it with the real syncapi.
+
+The shared-secret registration subtests of `TestRegistration` probe
+`/_synapse/admin/v1/register` and skip themselves when it 404s, which it
+does here: that endpoint is Synapse's, and `warp create-account` covers the
+same need.