fix: #33 内置多模态工具现在在工具市场 /api/v1/tools 中可见

list_tools 端点合并内置工具（image_ocr/image_vision/speech_to_text/text_to_speech 等），
按 scope=public/all 时自动包含，无需额外种子到 DB。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/models/orchestration_template.py

@@ -0,0 +1,27 @@
+"""
+编排模板模型 — 保存可视化 Agent 编排画布配置
+"""
+from sqlalchemy import Column, String, Text, JSON, DateTime, ForeignKey, func
+from sqlalchemy.dialects.mysql import CHAR
+from sqlalchemy.orm import relationship
+from app.core.database import Base
+import uuid
+
+
+class OrchestrationTemplate(Base):
+    """Agent 编排模板表"""
+    __tablename__ = "orchestration_templates"
+
+    id = Column(CHAR(36), primary_key=True, default=lambda: str(uuid.uuid4()), comment="模板ID")
+    name = Column(String(100), nullable=False, comment="模板名称")
+    description = Column(Text, comment="模板描述")
+    nodes = Column(JSON, nullable=False, comment="编排节点（含Agent配置）")
+    edges = Column(JSON, nullable=False, comment="编排连线")
+    user_id = Column(CHAR(36), ForeignKey("users.id"), comment="创建者ID")
+    created_at = Column(DateTime, default=func.now(), comment="创建时间")
+    updated_at = Column(DateTime, default=func.now(), onupdate=func.now(), comment="更新时间")
+
+    user = relationship("User", backref="orchestration_templates")
+
+    def __repr__(self):
+        return f"<OrchestrationTemplate(id={self.id}, name={self.name})>"