v0.12.4

Added

• Business hours schedule select on Admin/SlaPolicies/Form and
  Admin/Departments/Form. Shown only when the backend passes a schedules
  prop ([{ id, name }]); options are "Use the default" (null) and each
  schedule, posted as business_schedule_id. Business-hours SLA deadlines use
  the policy's schedule, else the ticket department's, else the default one.
  Pages rendered without schedules look and post exactly as before, so a
  backend without schedules never receives the field.
• Admin/Webhooks/Form supports backends that no longer send a webhook's
  signing secret. When the webhook prop has has_secret, the secret field
  starts blank, says "A secret is set. Leave blank to keep it." and offers
  Remove secret, which posts clear_secret: true (with Keep secret to
  undo). The form then always posts clear_secret. Backends that still send
  secret see no change: the field is filled in, posted back as it is, and
  clear_secret is not sent.
• Admin/Settings/SsoSettings says when a JWT shared secret or OAuth client
  secret is stored (the backend sends it as a mask such as ********). Leaving
  the field as it is posts the mask back, which keeps the stored secret.