feat(auth): change the password and the recovery phrase while signed in

ADR 0017, step 3. `password.beginChange` and `password.change` take the
old password's SRP proof and a TOTP or recovery code, and the same keys
wrapped under the new password; a session alone changes nothing, and an
account without a confirmed authenticator is told to set one up first.
`password.setRecoveryKeys` replaces the keys' wrapping under the
recovery phrase for a TOTP code, so a device holding the keys can make
a new phrase.

A change of password ends every other session of the account in every
service of the instance; resets of the password and of the account end
them all. The register ends its own and keeps a notice per member
(`sessions_ended_notice`, a migration that only creates it), told at
once and hourly until it confirms, as deletions are told: it names a
moment, so sessions made since stay, and the session that asked for a
change. A member answering one ends its sessions made before that
moment; a member signing someone in after a reset ends its own first
and makes the new session only once its clock is past the moment.

A reset not due says when it takes effect (`takesEffectAt` on
`PasswordRefusedException`), across members too.

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

apps/todo/halkyon_todo_server/migrations/20261020125124942-sessions-ended/definition_project.json

@@ -0,0 +1,29 @@
+{
+  "__className__": "serverpod.DatabaseDefinition",
+  "schemaVersion": 2,
+  "moduleName": "halkyon_todo",
+  "tables": [],
+  "installedModules": [
+    {
+      "__className__": "serverpod.DatabaseMigrationVersion",
+      "module": "halkyon_base",
+      "version": "20261020124836165-sessions-ended"
+    },
+    {
+      "__className__": "serverpod.DatabaseMigrationVersion",
+      "module": "serverpod",
+      "version": "20260824182259319"
+    },
+    {
+      "__className__": "serverpod.DatabaseMigrationVersion",
+      "module": "serverpod_auth_idp",
+      "version": "20260924105404509"
+    },
+    {
+      "__className__": "serverpod.DatabaseMigrationVersion",
+      "module": "serverpod_auth_core",
+      "version": "20260924105232991"
+    }
+  ],
+  "migrationApiVersion": 1
+}