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/run.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+# Run Complement against a freshly built Warp image.
+#
+#   server/test/complement/run.sh                 # the Phase 1 test set
+#   server/test/complement/run.sh TestLogin       # one test
+#   COMPLEMENT_TESTS='Test.*' server/test/complement/run.sh
+#
+# Complement is a separate Go module, so it has to be checked out and run on
+# its own. This script keeps that checkout in a cache directory rather than
+# vendoring it: it is a test harness we track, not a dependency we pin.
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../../.." && pwd)"
+
+: "${COMPLEMENT_REPO:=https://github.com/matrix-org/complement.git}"
+: "${COMPLEMENT_REF:=main}"
+: "${COMPLEMENT_DIR:=${REPO_ROOT}/.complement}"
+: "${COMPLEMENT_IMAGE:=complement-warp}"
+
+# The Phase 1 target set, from PLAN.md section 7. Add to it as phases land
+# rather than switching to the whole suite: a pass count that goes down
+# because a later phase is missing is noise.
+: "${COMPLEMENT_TESTS:=TestRegistration|TestLogin|TestDeviceManagement}"
+
+if [[ $# -gt 0 ]]; then
+	COMPLEMENT_TESTS="$(IFS='|'; echo "$*")"
+fi
+
+docker="${DOCKER:-docker}"
+if ! command -v "$docker" >/dev/null 2>&1; then
+	echo "complement: $docker is not installed; Complement needs a container runtime" >&2
+	exit 1
+fi
+
+echo "complement: building $COMPLEMENT_IMAGE"
+"$docker" build -t "$COMPLEMENT_IMAGE" -f "${REPO_ROOT}/server/test/complement/Dockerfile" "$REPO_ROOT"
+
+if [[ ! -d "$COMPLEMENT_DIR" ]]; then
+	echo "complement: cloning $COMPLEMENT_REPO into $COMPLEMENT_DIR"
+	git clone --depth 1 --branch "$COMPLEMENT_REF" "$COMPLEMENT_REPO" "$COMPLEMENT_DIR"
+else
+	git -C "$COMPLEMENT_DIR" fetch --depth 1 origin "$COMPLEMENT_REF"
+	git -C "$COMPLEMENT_DIR" checkout -q FETCH_HEAD
+fi
+
+echo "complement: running '${COMPLEMENT_TESTS}' with federation off"
+cd "$COMPLEMENT_DIR"
+
+# COMPLEMENT_SPAWN_HS_TIMEOUT_SECS is generous because the first container
+# of a run has to apply the migrations on a cold SQLite file.
+COMPLEMENT_BASE_IMAGE="$COMPLEMENT_IMAGE" \
+	COMPLEMENT_SPAWN_HS_TIMEOUT_SECS="${COMPLEMENT_SPAWN_HS_TIMEOUT_SECS:-60}" \
+	COMPLEMENT_DEBUG="${COMPLEMENT_DEBUG:-0}" \
+	go test -count=1 -v -timeout 20m -run "^(${COMPLEMENT_TESTS})$" ./tests/csapi/...