The provider-prefixed entries (deepseek/deepseek-chat, deepseek/deepseek-reasoner)
in the model cost map were missing supports_response_schema, supports_system_messages,
supports_native_streaming, supports_parallel_function_calling, and had stale
max_input_tokens / max_output_tokens values. This caused supports_response_schema()
to return False for DeepSeek models regardless of calling convention.
Changes:
- Sync deepseek/deepseek-chat and deepseek/deepseek-reasoner entries with
their canonical bare-name counterparts in both JSON files
- Add a bare-model-name fallback in _supports_factory so that when a
provider-prefixed entry is missing a capability field, the bare model
entry is consulted before returning False
- Fix pre-existing unused-import lint error (F401) in policy_resolve_endpoints.py
- Add 14 regression tests covering data consistency, API-level correctness,
and the new fallback logic
