docs: propose agent provider abstraction

[qian-le]

Summary

This PR adds a design proposal for an Agent Provider abstraction layer.

The goal is to explore how Edict could support multiple execution backends in the future while keeping the existing OpenClaw-based workflow unchanged.

Motivation

Edict already provides a strong multi-agent workflow console. Introducing a provider abstraction may make it easier to integrate with other local workflow tools, shell-based executors, Codex, Claude Code, CI jobs, or downstream personal workflow systems.

Scope

This PR only adds documentation.

It does not:

• change existing runtime behavior
• replace OpenClaw
• modify the UI
• introduce new dependencies
• implement any provider

Proposed Direction

The document suggests a possible AgentProvider interface and a phased migration path, starting with a minimal ShellProvider.

Notes

This is intended as a discussion-friendly proposal. I’m happy to adjust the direction based on maintainer feedback.

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中文说明

这个 PR 新增了一份关于 Agent Provider 抽象层的设计提案。

目标是在不改变现有 OpenClaw 工作流的前提下，讨论 Edict 未来是否可以支持更多执行后端，例如本地 shell 脚本、Codex、Claude Code、CI 任务，或下游个人工作流系统。

本 PR 仅包含文档，不会：

• 修改现有运行时行为
• 替换 OpenClaw
• 修改 UI
• 引入新依赖
• 实现任何 provider

文档中提出了一个可能的 AgentProvider 接口和分阶段迁移路径，并建议从最小的 ShellProvider 原型开始探索。

另外，文档也补充了 ClaudeCodeProvider 的受控代码修改思路：Claude Code 可以在隔离 workspace 或贡献分支中生成 patch、测试输出和变更摘要，但 commit、push 或 merge 仍应经过 Edict 的审核门禁。

这份提案主要用于开启讨论，我愿意根据维护者反馈调整方向。