feat: 添加观点传播系统

- 新增 Stance 数据结构 (optimism/fear)
- 情绪影响 stance (happy→乐观, anxious→恐惧)
- 实现 apply_social_influence 社交影响函数
- 确定性随机选择接触对象
- 单次变化限制 ±0.1

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

engine-python/app/opinions.py

@@ -1,6 +1,13 @@
 """角色事件评论系统 - 基于规则生成观点"""
 from typing import Dict, List, Optional
-from .models import WorldState, AgentState, Opinion, Emotion, WorldEffect
+from .models import WorldState, AgentState, Opinion, Emotion, WorldEffect, Stance
+
+# 情绪对 stance 的影响
+EMOTION_STANCE_EFFECTS: Dict[str, Dict[str, float]] = {
+    "happy": {"optimism": 0.1, "fear": -0.05},
+    "calm": {"optimism": 0.0, "fear": 0.0},
+    "anxious": {"optimism": -0.05, "fear": 0.1},
+}
 
 
 # 观点模板：effect_type -> emotion -> 观点列表
@@ -123,6 +130,20 @@ def get_opinion_text(
     return templates[index]
 
 
+def update_stance_from_emotion(agent: AgentState) -> None:
+    """根据情绪更新 stance（单次变化不超过 ±0.1）"""
+    emotion_key = agent.emotion.value
+    effects = EMOTION_STANCE_EFFECTS.get(emotion_key, {})
+
+    # 更新 optimism
+    new_optimism = agent.stance.optimism + effects.get("optimism", 0.0)
+    agent.stance.optimism = max(0.0, min(1.0, new_optimism))
+
+    # 更新 fear
+    new_fear = agent.stance.fear + effects.get("fear", 0.0)
+    agent.stance.fear = max(0.0, min(1.0, new_fear))
+
+
 def generate_opinions(state: WorldState) -> None:
     """为所有 agent 生成对当前活跃事件的观点"""
     # 无活跃效果时，清空 opinion
@@ -155,6 +176,9 @@ def generate_opinions(state: WorldState) -> None:
             tick=state.tick
         )
 
+        # 根据情绪更新 stance
+        update_stance_from_emotion(agent)
+
         # 记录到 memory
         memory_entry = f"[{agent_id}对{active_effect.name}的看法] {text}"
         agent.memory.append(memory_entry)