1b39aae7c4
12 tests fail with: TypeError: NormalizedResponse.__init__() got an unexpected keyword argument 'usage_input_tokens' The @dataclass(frozen=True) auto-generated __init__ requires `usage: UsageStats`, but 12 tests + 1 production site (src/ai_client.py:908) call it with the OLD flat-kwarg API (usage_input_tokens=..., usage_output_tokens=..., etc.). Change @dataclass(frozen=True) -> @dataclass(frozen=True, init=False) and add a custom __init__ that accepts BOTH signatures: - New: usage: UsageStats (used by current production code) - Legacy: usage_input_tokens, usage_output_tokens, usage_cache_read_tokens, usage_cache_creation_tokens (used by tests + 1 ai_client site) If usage is None and any legacy flat kwarg is non-None, build a UsageStats from the legacy kwargs. Otherwise use the provided usage. All field assignments use object.__setattr__ because frozen=True locks __setattr__. Verification: - Legacy kwargs work: NormalizedResponse(text="hi", tool_calls=(), usage_input_tokens=10, usage_output_tokens=5, raw_response=None) sets usage.input_tokens=10 - New kwargs work: NormalizedResponse(text="hi", tool_calls=(), usage=UsageStats(1, 2)) sets usage directly - 12 affected tests now pass (was 12 failed, 3 passed; now 15 passed)