DeepSeek provider bundle.
Purpose
-------
Importing this package registers :class:`DeepSeekProvider` into the
module-level registry at ``oc_chat.core.provider_plugin.registry``.
The rest of the app then retrieves it via ``registry.get("deepseek")``.
Responsibilities
----------------
- Self-register :class:`DeepSeekProvider` on import (Phase C.1c
contract).
- Re-export :class:`DeepSeekProvider` for direct access.
Diagnostics
-----------
Domain: OC_CHAT.CLIENT
Levels:
L2 — lifecycle events
L3 — semantic details
L4 — deep tracing
Contracts
---------
- Side effect on import: ``DeepSeekProvider.register()`` runs once.
Repeated imports are idempotent (the registry detects same-name +
same-class registrations and skips silently).
- ``__all__`` deliberately exposes only the provider class — bundle
internals (``client``, ``models``, ``cache_usage``) are private to
the bundle.
Dependencies
------------
- oc_diagnostics (structured debug logging via _dbg)
- providers.deepseek.provider (DeepSeekProvider, registered on import and re-exported)