feat: 用户行为信誉分系统

- User 新增 credit_score 字段（0-200，默认100）
- 信誉分影响检测阈值系数：高分降低敏感度，低分提高敏感度
- 发布成功+1分，被拦截-2分；申诉通过+10分，驳回-5分
- 新增手动调整和批量重算信誉分接口
- admin-users 页面显示信誉分进度条，支持编辑调整

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/app/routes/admin_routes.py

@@ -309,11 +309,17 @@ def process_appeal(post_id: int):
         row.prediction = "ham"
         row.manual_review_status = "approved_ham"
         _upsert_manual_sample(row.text, "ham", admin.id if admin else None)
+        # 申诉通过，增加用户信誉分
+        if row.author:
+            row.author.credit_score = min(200, (row.author.credit_score or 100) + 10)
     else:
         row.status = "blocked"
         row.prediction = "spam"
         row.manual_review_status = "confirmed_spam"
         _upsert_manual_sample(row.text, "spam", admin.id if admin else None)
+        # 申诉驳回，减少用户信誉分
+        if row.author:
+            row.author.credit_score = max(0, (row.author.credit_score or 100) - 5)
 
     db.session.commit()
     return ok(_serialize_post(row), "申诉处理完成")
@@ -404,6 +410,12 @@ def update_user(user_id: int):
         user.phone = (payload.get("phone") or "").strip()
     if "is_admin" in payload:
         user.is_admin = bool(payload.get("is_admin"))
+    if "credit_score" in payload:
+        try:
+            credit = int(payload.get("credit_score", 100))
+            user.credit_score = max(0, min(200, credit))
+        except Exception:
+            pass
     if payload.get("password"):
         if len(payload["password"]) < 6:
             return fail("密码至少6位", 400)
@@ -427,3 +439,73 @@ def delete_user(user_id: int):
     db.session.commit()
     return ok({}, "用户已删除")
 
+
+@admin_bp.put("/users/<int:user_id>/credit")
+@admin_required
+def update_user_credit(user_id: int):
+    """手动调整用户信誉分"""
+    user = User.query.get(user_id)
+    if not user:
+        return fail("用户不存在", 404)
+
+    payload = request.get_json(silent=True) or {}
+    try:
+        credit = int(payload.get("credit_score", user.credit_score or 100))
+        credit = max(0, min(200, credit))
+    except Exception:
+        return fail("信誉分必须是0-200之间的整数", 400)
+
+    user.credit_score = credit
+    db.session.commit()
+    return ok(user.to_dict(), "信誉分已更新")
+
+
+@admin_bp.post("/users/recalculate-credit")
+@admin_required
+def recalculate_all_credit():
+    """根据用户发布历史和申诉通过率重新计算信誉分"""
+    users = User.query.filter_by(is_admin=False).all()
+    updated_count = 0
+
+    for user in users:
+        posts = ContentPost.query.filter_by(user_id=user.id).all()
+        if not posts:
+            continue
+
+        # 计算发布成功率
+        published_count = sum(1 for p in posts if p.status == "published")
+        blocked_count = sum(1 for p in posts if p.status == "blocked")
+        total_count = len(posts)
+
+        if total_count == 0:
+            continue
+
+        publish_ratio = published_count / total_count
+
+        # 计算申诉通过率
+        appeals = [p for p in posts if p.appeal_status != "none"]
+        approved_appeals = sum(1 for p in appeals if p.appeal_status == "approved")
+        appeal_ratio = approved_appeals / len(appeals) if appeals else 0
+
+        # 基础信誉分：发布成功率贡献
+        base_score = 100
+        if publish_ratio >= 0.9:
+            base_score += 30  # 90%以上发布成功，+30
+        elif publish_ratio >= 0.7:
+            base_score += 15  # 70%以上，+15
+        elif publish_ratio < 0.5:
+            base_score -= 20  # 低于50%，-20
+
+        # 申诉通过率贡献
+        if appeal_ratio >= 0.8 and len(appeals) >= 3:
+            base_score += 20  # 80%以上申诉通过且有3次以上申诉，+20
+        elif appeal_ratio >= 0.5 and len(appeals) >= 2:
+            base_score += 10
+
+        # 限制范围
+        user.credit_score = max(0, min(200, base_score))
+        updated_count += 1
+
+    db.session.commit()
+    return ok({"updated_count": updated_count}, "信誉分批量重算完成")
+