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/models/lead_capture.py

@@ -0,0 +1,118 @@
+"""
+Copyright 2024-2026 ChatterMate
+
+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 import (
+    Column, Integer, String, Boolean, DateTime, ForeignKey,
+    Enum as SQLEnum, JSON, Text, func, false, true,
+)
+from sqlalchemy.orm import relationship
+from sqlalchemy.dialects.postgresql import UUID
+import enum
+import uuid
+from app.database import Base
+
+
+class LeadAssignmentMode(str, enum.Enum):
+    """Where a qualified lead is routed. Phase 1: stored only, not acted on."""
+    NONE = "none"
+    SALES_TEAM = "sales_team"
+    SPECIFIC_PERSON = "specific_person"
+    ROUND_ROBIN = "round_robin"
+
+
+class CrmSyncTarget(str, enum.Enum):
+    """Which CRM a qualified lead syncs to.
+
+    Stored as a plain string column (not a DB enum) so adding a CRM never
+    requires a schema migration — mirrors ChannelType. str() is the value so
+    in-memory enum instances and refreshed-from-DB strings render identically.
+    """
+
+    NONE = "none"
+    HUBSPOT = "hubspot"
+    PIPEDRIVE = "pipedrive"
+    SALESFORCE = "salesforce"
+
+    def __str__(self) -> str:  # pragma: no cover - trivial
+        return self.value
+
+
+class LeadCaptureConfig(Base):
+    """Per-agent lead-capture configuration (1:1 with Agent).
+
+    Prompt-driven, like transfer_to_human: a simple on/off toggle. When enabled, the
+    agent collects the configured fields conversationally (no form) and emits them as
+    structured output plus an AI-written lead summary.
+    """
+    __tablename__ = "lead_capture_configs"
+
+    id = Column(Integer, primary_key=True, index=True)
+    agent_id = Column(
+        UUID(as_uuid=True),
+        ForeignKey("agents.id", ondelete="CASCADE"),
+        unique=True,
+        nullable=False,
+    )
+    # Master toggle (mirrors Agent.transfer_to_human).
+    enabled = Column(Boolean, default=False, server_default=false(), nullable=False)
+    # GDPR: require the visitor's explicit "yes" before a lead is recorded (default on).
+    require_consent = Column(Boolean, default=True, server_default=true(), nullable=False)
+
+    # Free-text steering appended to the agent's system prompt (e.g. "prioritise
+    # pricing-page visitors, be proactive after hours"). The agent decides *when* to ask.
+    guidance = Column(Text, nullable=True)
+    # Which details to collect — feeds the prompt and defines the expected lead_data keys:
+    #  {"key": "email", "standard": true, "required": true, "enabled": true}
+    #  {"key": "custom_1", "standard": false, "label": "Team size", "enabled": true}
+    fields = Column(JSON, nullable=True)
+
+    # Routing config — persisted so the shape is ready for real integration later,
+    # but never acted on in phase 1 (no CRM/Slack/assignment side effects).
+    assignment_mode = Column(SQLEnum(LeadAssignmentMode), default=LeadAssignmentMode.NONE, server_default="NONE", nullable=False)
+    assignment_target_user_id = Column(UUID(as_uuid=True), ForeignKey("users.id"), nullable=True)
+    crm_sync_target = Column(String(32), default=CrmSyncTarget.NONE.value, server_default="none", nullable=False)
+    slack_notify_enabled = Column(Boolean, default=False, server_default=false(), nullable=False)
+
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    # Relationships
+    agent = relationship("Agent", back_populates="lead_capture_config", uselist=False)
+
+
+class LeadCaptureResponse(Base):
+    """One row per captured lead — the fields the agent extracted conversationally,
+    plus an AI-written qualification summary. Kept separate from Customer.meta_data
+    (integrator-supplied) so AI-captured leads have a clean home."""
+    __tablename__ = "lead_capture_responses"
+
+    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    organization_id = Column(UUID(as_uuid=True), ForeignKey("organizations.id"), nullable=False)
+    agent_id = Column(UUID(as_uuid=True), ForeignKey("agents.id", ondelete="SET NULL"), nullable=True)
+    customer_id = Column(UUID(as_uuid=True), ForeignKey("customers.id", ondelete="CASCADE"), nullable=False)
+    session_id = Column(UUID(as_uuid=True), ForeignKey("session_to_agents.session_id"), nullable=True)
+
+    field_values = Column(JSON, nullable=True)  # {"email": ..., "company": ..., "custom_1": ...}
+    # AI-written qualification narrative (e.g. "40-person fintech replacing Intercom, wants a demo").
+    summary = Column(Text, nullable=True)
+    # Whether the visitor gave explicit consent to be contacted (GDPR).
+    consent = Column(Boolean, default=False, nullable=False)
+    qualified = Column(Boolean, default=False, nullable=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+
+    # Relationships
+    customer = relationship("Customer", back_populates="lead_capture_responses")
+    agent = relationship("Agent")