[P3.9] `get_provider()` silently drops model/base_url overrides for the Anthropic provider

[frankbria]

Severity: low | Category: ux | Phase: P3.9

Problem

The anthropic branch returns AnthropicProvider() ignoring all kwargs, so --llm-model/CODEFRAME_LLM_MODEL/config llm.model are silently discarded for anthropic.

Evidence

codeframe/adapters/llm/__init__.py:87

Acceptance criteria

Honor model on the anthropic path (via ModelSelector), or log/reject unsupported kwargs so the drop isn't silent.

Dependencies

None

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_{Filed from the SaaS launch-readiness audit. Atomic: one developer, one session. Work order: strictly P0.1 → P3.12 (no forward dependencies).}