feat(base)!: sign-ups as the operator says, waiting accounts, operators (ADR 0021, step 1)

SIGN_UP takes open (unset), approval or closed; anything else stops the
server as it starts. Closed refuses a SimpleLogin sign-up before its
handle is counted, an address sign-up only once the code has proved the
address, so nothing tells whether an address has an account. Approval
lets a new account wait, at most ten at once: no session is issued for a
waiting or suspended account, only a pass (32 random bytes, kept as its
SHA-256, 30 days, five per account) and four BIP-39 words the operator
reads out to match it. The pass looks, forgets, and deletes an account
that was never approved; nothing else.

Operators hold the scope operator, given first by SQL (D32), then named
in the app: InstanceOperatorEndpoint lists, approves and refuses waiting
accounts, finds accounts, suspends them (ending their sessions), and
names and takes back operators, never the last. account.operating()
counts the waiting for the badge. Members ask the register (five new
operations, a refusal kind signUp), and say closed while it is out of
reach. Never-approved accounts go after 14 days in the daily pruning.

The migration only adds the tables waiting_account and waiting_pass, so
the server before it keeps working on the new schema.

BREAKING CHANGE: a register and its members must run this version
together: a member asks the register operations an older one doesn't
know.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

packages/halkyon_base_server/pubspec.yaml

@@ -20,6 +20,10 @@ dependencies:
   # 0017): what a server needs of both, without libsodium. Pinned exactly, as
   # what keeps secrets must never move by accident.
   cryptography: 2.9.0
+  # BIP-39's English list, which a waiting account's matching code is of
+  # (Halkyon Learn's ADR 0021, D33).
+  halkyon_core:
+    path: ../halkyon_core
   # Signing in with SimpleLogin (ADR 0020), on the OpenID Connect module
   # (ADR 0023).
   halkyon_oidc_server: