feat(sop): support SOP in both sdk and service level

**Background**

Based on extensive user feedback, there is a strong demand for **highly deterministic SOP (Standard Operating Procedure) capabilities** to ensure task completeness and verifiability. To address this, we are planning to introduce SOP support at both the **SDK level** and **service level** within AgentScope.

**Notes**

1. **SOP is not a static graph** — The goal is not to build a static graph execution engine like LangGraph. Instead, SOP is designed to support **deterministic, repeatable multi-agent collaborative tasks**.

2. **SOP is user-facing, not agent-facing** — SOP is not a planning mechanism. It is **created by users**, not agents. Agents may have visibility into SOPs and, depending on the service configuration, may be able to execute them or inspect their runtime status — but agents cannot create SOPs (at least for now).

3. **This effort will also address the collaboration between pipeline editing and HITL (Human-in-the-Loop)** introduced in v2, resolving existing coordination issues between the two.