feat(models): 组织、用户、角色、客户、会话与消息模型

按组织边界定义数据关系，补齐仓储层与通用工具，迁移脚本可重复执行。

backend/app/repositories/lead_capture.py

@@ -0,0 +1,60 @@
+"""
+Copyright 2024-2026 ReplyPier
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+"""
+
+from sqlalchemy.orm import Session
+from typing import Optional
+from uuid import UUID
+
+from app.models.lead_capture import LeadCaptureConfig
+from app.models.schemas.lead_capture import LeadCaptureConfigUpdate
+
+
+class LeadCaptureConfigRepository:
+    def __init__(self, db: Session):
+        self.db = db
+
+    def get_by_agent(self, agent_id: UUID) -> Optional[LeadCaptureConfig]:
+        return (
+            self.db.query(LeadCaptureConfig)
+            .filter(LeadCaptureConfig.agent_id == agent_id)
+            .first()
+        )
+
+    def get_or_create(self, agent_id: UUID) -> LeadCaptureConfig:
+        """Return the agent's config, lazily creating a default (disabled) row —
+        mirrors how AgentCustomization is fetched-or-created."""
+        config = self.get_by_agent(agent_id)
+        if config is None:
+            config = LeadCaptureConfig(agent_id=agent_id, enabled=False)
+            self.db.add(config)
+            self.db.commit()
+            self.db.refresh(config)
+        return config
+
+    def update(self, agent_id: UUID, data: LeadCaptureConfigUpdate) -> LeadCaptureConfig:
+        """Full-replace the config from a validated payload."""
+        config = self.get_or_create(agent_id)
+        config.enabled = data.enabled
+        config.require_consent = data.require_consent
+        config.guidance = data.guidance
+        config.fields = [f.model_dump() for f in data.fields]
+        config.assignment_mode = data.assignment_mode
+        config.assignment_target_user_id = data.assignment_target_user_id
+        config.crm_sync_target = data.crm_sync_target
+        config.slack_notify_enabled = data.slack_notify_enabled
+        self.db.commit()
+        self.db.refresh(config)
+        return config