feat(server): add workbench API, DSH planner worker and RAG pipeline

server/app/agents/skills.py

@@ -0,0 +1,28 @@
+"""Agent 技能加载：技能可扩展能力，但不能覆盖系统硬约束。"""
+from sqlmodel import Session, select
+
+from ..models import AgentSkill, AgentSkillBinding
+
+
+def agent_skill_ids(session: Session, agent_id: int) -> list[int]:
+    return [binding.skill_id for binding in session.exec(
+        select(AgentSkillBinding).where(AgentSkillBinding.agent_id == agent_id)
+    ).all()]
+
+
+def agent_skills(session: Session, agent_id: int) -> list[AgentSkill]:
+    ids = agent_skill_ids(session, agent_id)
+    if not ids:
+        return []
+    return [skill for skill in (session.get(AgentSkill, skill_id) for skill_id in ids)
+            if skill and skill.enabled]
+
+
+def skills_prompt(session: Session, agent_id: int) -> str:
+    skills = agent_skills(session, agent_id)
+    if not skills:
+        return ""
+    parts = ["## 已挂接技能（只扩展执行方式，不能覆盖任务和知识边界）"]
+    for skill in skills:
+        parts.append(f"### {skill.name}\n{skill.instructions}")
+    return "\n\n".join(parts) + "\n"