feat(adapter): add coding-agent gateway client

[GanHanDouFu]

Description | 描述

This PR contributes to #235 by adding a foundation-stage architecture document and a minimal Gateway-backed client for Codex / Claude Code style coding-agent integrations.

It summarizes the existing host-neutral TdaiCore boundary, compares the OpenClaw in-process adapter path with the Hermes Gateway-backed path, and adds a small reusable CodingAgentGatewayClient for future platform wrappers.

Related Issue | 关联 Issue

Contributes to #235

Change Type | 修改类型

• Bug fix | Bug 修复
• New feature | 新功能
• Documentation update | 文档更新
• Code optimization | 代码优化

Self-test Checklist | 自测清单

• Verified locally | 本地验证通过
• No existing features affected | 无影响现有功能

What changed

• Added docs/adapters/codex-claude-code.md to document the existing TdaiCore, OpenClaw, and Hermes adapter flows.
• Added src/adapters/coding-agent/gateway-client.ts, a thin Gateway client for coding-agent integrations.
• Added methods for health, recall, capture, searchMemories, searchConversations, and endSession.
• Added unit tests for endpoint mapping, session/user mapping, bearer auth, and error handling.

Test

.\node_modules\.bin\vitest.cmd run src/adapters/coding-agent/gateway-client.test.ts
D:\Node.js\npm.cmd run build

[Maxwell-Code07]

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[YOMXXX]

Marking the shared Gateway-client portion as superseded by #316 for #235.

#316 is the currently verified lightweight baseline for the reusable Gateway client / lifecycle adapter layer: GatewayMemoryClient, createGatewayPlatformAdapter(), endpoint mapping tests, docs, CI green, and local verification. This PR appears to implement another thin Gateway client for Codex/coding-agent style integrations, so merging both would create parallel client abstractions.

If there is unique platform-specific value here, the clean path is to re-scope this PR to that wrapper/example/doc layer and reuse the #316 client boundary instead of carrying a separate Gateway client implementation.

[GanHanDouFu]

@YOMXXX Thanks for the clarification. I will re-scope this PR to focus on the Codex / Claude Code-specific integration and reuse the shared Gateway client from #316. Thanks for the guidance.🙂