feat: create the initial platform owner from an operator command

A fresh production installation deadlocked. ADR 0034 gave Ekklesia a login
page and ADR 0019 gave it a single-use platform-owner bootstrap, but that
bootstrap grants ownership to a user id that already exists and has no way
to bring one into being. Public signup is disabled by default and
production cannot enable it at all, so a newly deployed instance had a
login page, no account, and no supported way to create one — only hand-
written SQL or briefly opening public registration.

    pnpm identity:create-initial-owner -- --email [email protected]

creates the identity and grants it ownership, in the same shape as the
other operator commands: trusted local tooling, reachable only by someone
who already holds the database credentials, serving no HTTP route. No
/signup, /register, or /setup route is added, no bootstrap endpoint, and
no setup token; public signup stays disabled in every environment and a
test asserts a freshly bootstrapped deployment still refuses
/api/auth/sign-up/email.

The identity is created through Better Auth's own sign-up path, so
hashing, salting, normalization and the 8-128 bound are the identity
system's rather than a second implementation that could drift. Because the
server's instance refuses account creation, the command builds its own
in-process instance; nothing in apps/api imports it and the running
server's posture is untouched.

The sign-up result is verified rather than trusted. Better Auth returns a
fabricated success for an already-registered address — a user object whose
id was never persisted, database unchanged. That is correct enumeration
defence on a public endpoint and a trap here, so the identity is always
read back from the database and that read, not the response, is what the
grant uses.

An existing usable identity is adopted: ownership is granted and its
password left alone, reported as an adoption rather than a creation. This
is the recovery path for the one partial failure possible, since sign-up
commits on Better Auth's connection and the grant is a separate
transaction. A credential-less row is refused instead — making it an owner
would consume the single use on an identity nobody can authenticate as. A
password is never reset and an account is never taken over.

Whole invocations are serialized by an advisory lock on their own key, so
a race cannot leave a stray signable-in account behind; the grant's own
locked single-use transaction is unchanged. There is no --force or reset.

The password is prompted for invisibly or read from stdin, never from
argv (--password is refused with an explanation) and never from an
environment variable, so nothing about it becomes permanent deployment
configuration. The command needs DATABASE_URL and nothing else — verified
that sign-up needs no secret, base URL, or trusted origins, and that the
resulting account signs in through a separately configured server — so the
first owner can be created before TLS or DNS exist. It never migrates.

Proven end to end rather than at the database: a fresh installation is
bootstrapped, signed in through the real browser login transport with
signup disabled, its principal read, and used to open an owner-protected
resource that stays closed to anonymous callers.

Co-Authored-By: Claude Opus 5 <[email protected]>

docs/development/security.md

@@ -506,6 +506,44 @@ outstanding.
     consuming the single-use platform-owner bootstrap. This repository does not provide that way
     yet.
 
+### The initial-owner command is trusted local tooling
+
+A fresh installation needs a first administrator, and public registration is disabled everywhere and
+prohibited in production. `pnpm identity:create-initial-owner` fills that gap
+([ADR 0035](../architecture/decisions/0035-initial-platform-owner-bootstrap.md)). What makes it safe
+is **where it can be invoked**, not a weaker policy:
+
+- **It is not reachable from a browser.** No `/signup`, `/register`, or `/setup` route, no
+  unauthenticated bootstrap endpoint, no temporary setup route, and no setup token. It serves no HTTP
+  route and nothing in `apps/api` imports it. Its authority is already having the database
+  credentials.
+- **Public signup stays disabled.** The command constructs its own in-process identity instance
+  rather than relaxing the server's posture. A test asserts that a freshly bootstrapped deployment
+  still refuses `POST /api/auth/sign-up/email`.
+- **The password never lands anywhere durable.** Prompted invisibly or read from standard input;
+  `--password` is refused rather than ignored, because an argument is visible in shell history and in
+  the process list. No environment variable is read for it and none is in `.env.example`, so it
+  cannot become permanent deployment configuration. It is never printed, logged, or placed in an
+  error.
+- **It writes no password hash of its own.** Hashing, salting, normalization, and the 8–128 bound are
+  the identity system's, applied through the same sign-up path a browser uses — so a CLI-created
+  account can never diverge from a browser-created one.
+- **It cannot become a standing superuser factory.** Ownership bootstrap is permanently single-use
+  and this command consumes the same sentinel; there is no `--force`, reset, or override. A second
+  run creates no owner, changes no password, and creates no stray identity.
+- **It never takes over an account.** An existing usable identity is adopted — granted ownership with
+  its password untouched — and reported as an adoption. A password reset is never performed. An
+  identity that has no password at all is refused rather than made an owner nobody can sign in as,
+  which would consume the single use and leave the installation unusable.
+- **Races cannot mint two owners.** Whole invocations are serialized by an advisory lock, on top of
+  the grant's own locked, single-use transaction.
+- **Errors stay sanitized.** No SQL, connection string, driver detail, Better Auth response body, or
+  cause reaches the operator's terminal — only a stable code and a message describing what is still
+  true of the installation.
+
+It deliberately does not solve creating *additional* users or owners. That is user administration,
+which does not exist yet.
+
 ### Rate limiting is per-process today
 
 Better Auth's authentication rate limiter is **in-memory and per API process**. That is acceptable