feat(backend): add ontology and orchestrator API endpoints

New endpoints:
- server/src/app/api/v1/endpoints/ontology.py: ontology API
- server/src/app/api/v1/endpoints/orchestrator.py: orchestrator API

New schemas:
- server/src/app/schemas/ontology.py: ontology data schemas
- server/src/app/schemas/orchestrator.py: orchestrator data schemas
- server/src/app/schemas/user_agent.py: user agent data schemas

New services:
- server/src/app/services/ontology.py: ontology business logic
- server/src/app/services/orchestrator.py: orchestrator business logic
- server/src/app/services/runtime_chat.py: runtime chat service
- server/src/app/services/user_agent.py: user agent service

New tests:
- server/tests/test_ontology_service.py
- server/tests/test_orchestrator_service.py
- server/tests/test_user_agent_service.py

server/src/app/schemas/orchestrator.py

@@ -0,0 +1,46 @@
+from __future__ import annotations
+
+from typing import Any, Literal
+
+from pydantic import BaseModel, Field
+
+OrchestratorSource = Literal["user_message", "schedule", "system_event"]
+OrchestratorAgent = Literal["user_agent", "hermes"]
+OrchestratorStatus = Literal["succeeded", "blocked", "failed"]
+
+
+class OrchestratorRequest(BaseModel):
+    source: OrchestratorSource = Field(description="请求来源。")
+    user_id: str | None = Field(default=None, description="当前用户 ID，任务触发可为空。")
+    message: str | None = Field(default=None, description="用户消息或任务描述。")
+    task_id: str | None = Field(default=None, description="任务资产 ID，schedule 触发时优先使用。")
+    context_json: dict[str, Any] = Field(
+        default_factory=dict,
+        description="用户上下文、测试开关或调用方附加信息。",
+    )
+
+
+class OrchestratorTraceSummary(BaseModel):
+    scenario: str = Field(description="语义场景。")
+    intent: str = Field(description="语义意图。")
+    tool_count: int = Field(default=0, ge=0, description="工具调用总数。")
+    failed_tool_count: int = Field(default=0, ge=0, description="失败工具调用数量。")
+    selected_capability_codes: list[str] = Field(
+        default_factory=list,
+        description="本次路由命中的能力编码。",
+    )
+    degraded: bool = Field(default=False, description="是否发生降级。")
+
+
+class OrchestratorResponse(BaseModel):
+    run_id: str = Field(description="本次运行的唯一 run_id。")
+    selected_agent: OrchestratorAgent | None = Field(
+        default=None,
+        description="最终路由到的下游 Agent。",
+    )
+    route_reason: str = Field(description="路由原因摘要。")
+    permission_level: str = Field(description="权限级别。")
+    status: OrchestratorStatus = Field(description="最终运行状态。")
+    result: dict[str, Any] = Field(default_factory=dict, description="对前端可直接展示的最小结果。")
+    requires_confirmation: bool = Field(default=False, description="是否需要用户或管理员确认。")
+    trace_summary: OrchestratorTraceSummary = Field(description="简化后的 Trace 摘要。")