feat(feishu): add FEISHU_AUTO_THREAD for automatic thread replies

[nick2781]

Summary

• Adds FEISHU_AUTO_THREAD env var (default: false) that, when enabled, makes all Feishu replies land inside threads automatically
• Each new inbound message creates a new thread, isolating conversation context per thread and preventing unrelated conversations from mixing and exhausting the context window
• Works for both streaming and non-streaming reply paths

How it works

Feishu's reply API supports a reply_in_thread flag, but the create API does not. Many code paths (streaming, agent tool calls) use create because they don't have a reply_to message ID.

This PR:

1. Tracks the last inbound message_id per chat_id in FeishuAdapter
2. In _send_raw_message, when FEISHU_AUTO_THREAD=true and no reply_to is provided, automatically uses the tracked message ID — routing through the reply API with reply_in_thread=true
3. Passes an initial reply_to to GatewayStreamConsumer so streaming replies also land in threads

Configuration

# In ~/.hermes/.env
FEISHU_AUTO_THREAD=true

Defaults to false — no behavior change for existing users.

Test plan

• Verified in private chat: replies appear inside threads
• Verified reply_in_thread=true is set in the reply API call
• Verified backward compatibility: without FEISHU_AUTO_THREAD, behavior is unchanged

🤖 Generated with Claude Code

[nick2781]

@teknium1 Is there somebody can do the code review?

[alt-glitch]

Related to #9118 (Feishu auto-thread PR) and #9154 (feature request). May overlap — check for merge conflicts.

[teknium1]

Thanks for the clear Feishu threading investigation and for covering both ordinary and streaming reply paths.

This automated hermes-sweeper review is closing the PR under the standing configuration policy:

• The PR introduces FEISHU_AUTO_THREAD as a user-facing behavioral switch and documents setting it in .env (gateway/platforms/feishu.py, PR head 5e413166dc1c).
• AGENTS.md:102-107 requires non-secret behavior settings and feature flags to use config.yaml, not new environment-variable configuration.
• The current gateway has a plugin-owned YAML configuration path (gateway/config.py:1252-1287); Feishu registers its bridge in plugins/platforms/feishu/adapter.py:5618-5654.
• Related PR feat(gateway): Feishu auto-thread and topic-based session routing #9118 was already closed on the same env-var-for-config policy for its FEISHU_AUTO_THREAD implementation.

Please re-scope a follow-up around Feishu YAML configuration through the plugin bridge, preserving thread_id as the topic identity. This is a design-direction decision, not a judgment on the implementation quality.

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Automated hermes-sweeper review.

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Closed as not-planned per standing maintainer policy (env-var-for-config). This is a design-direction decision, not a code-quality judgment — see the Contribution Rubric in AGENTS.md for what the project is looking for. If you believe this policy was misapplied to your change, comment here and a maintainer will take a look.