"""Platform-wide content: rotating 制度公告 (policy / manual notices).

Surfaces a small rotating ribbon in the app header (frontend
``PolicyNoticesBanner``) that cycles through admin-curated links to
company policies, regulations, and handbooks. Each notice is a bilingual
title (zh-CN + en-US, picked at render time by the user's session
language) plus a Feishu document URL — clicking the ribbon opens the doc
in a new tab.

Distinct from the security-awareness ribbon (``platform_tips`` →
``ITServiceDeskMascot`` bubble): that domain pushes short text reminders,
this one links out to long-form policy/manual documents. The header slot
the security ribbon used to occupy (now freed, since security tips moved
to the mascot) is reused here.

Admin-managed (CRUD at ``/admin/policy-notices``), individually
toggleable, and ordered. The banner hides itself when zero notices are
enabled. Mutations are global_admin-gated and audited at the service
layer (``platform.policy_notice.<verb>``).
"""