chore: 删除从未被调用的 /api/personal_dynamics 端点

`POST /api/personal_dynamics`（system_router.py:7385）在整个仓库（含 static/、
templates/、NEKO-PC/、tests/）grep 不到任何前端或外部 HTTP 调用方；后端唯一
真正消费 personal_dynamics 数据的地方是 proactive_chat handler 内部直接
`await fetch_personal_dynamics(...)`（system_router.py:5249），不经过自身
的 HTTP 路由。

死代码 + 命名违和（资源型路径却用 POST），按"发现即清理"原则一并删除。
`fetch_personal_dynamics` / `format_personal_dynamics` / `_log_personal_dynamics`
全部保留——它们仍被 proactive_chat 使用。

verified: uv run pytest tests/unit/ -k "personal or proactive" -v → 163 passed

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: LyaQanYi

main_routers/system_router.py

@@ -7380,50 +7380,6 @@ async def translate_text_api(request: Request):
             "target_lang": "zh"
         }
 
-# ========== 个性化内容接口 ==========
-
-@router.post('/personal_dynamics')
-async def get_personal_dynamics(request: Request):
-    """
-    获取个性化内容数据
-    """
-    from utils.web_scraper import fetch_personal_dynamics, format_personal_dynamics
-    try:
-        
-        data = await request.json()
-        limit = data.get('limit', 10)
-        
-        # 获取个性化内容
-        personal_content = await fetch_personal_dynamics(limit=limit)
-        
-        if not personal_content['success']:
-            return JSONResponse({
-                "success": False,
-                "error": "无法获取个性化内容",
-                "detail": personal_content.get('error', '未知错误')
-            }, status_code=500)
-        
-        # 格式化内容用于前端显示
-        formatted_content = format_personal_dynamics(personal_content)
-        
-        return JSONResponse({
-            "success": True,
-            "data": {
-                "raw": personal_content,
-                "formatted": formatted_content,
-                "platforms": [k for k in personal_content.keys() if k not in ('success', 'error', 'region')]
-            }
-        })
-        
-    except Exception as e:
-        logger.error(f"获取个性化内容失败: {e}")
-        return JSONResponse({
-            "success": False,
-            "error": "服务器内部错误",
-            "detail": str(e)
-        }, status_code=500)
-
-
 # Self-register the mini-game-invite keyword matcher with main_logic's
 # event bus. Same rationale as plugin/core/state.py: ``main_logic.core``
 # previously imported this function directly (a layering inversion);