feat(core): 添加 LLMResponse frozen dataclass

含 content/thinking/ttft_ms/max_inter_token_ms/call_id 等 11 个字段。

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

core/types.py

@@ -1 +1,24 @@
 """跨模块共享类型。"""
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class LLMResponse:
+    """LLM/VLM 调用的统一返回值。
+
+    由 adapters 层生成，core 层消费。frozen=True 确保响应不可变。
+    """
+
+    content: str
+    thinking: str
+    model: str
+    provider: str
+    prompt_tokens: int
+    completion_tokens: int
+    latency_ms: int
+    ttft_ms: float | None
+    max_inter_token_ms: float | None
+    cache_hit: bool
+    call_id: str