fix(honcho): buffer turns during async session initialization

[c0d1ngHUB]

Summary

• buffer completed turns while an asynchronous Honcho session is still initializing
• drain queued turns in FIFO order through one async writer once initialization succeeds
• fail open on permanent initialization failure or shutdown, with bounded, content-free queue handling
• add regression coverage for startup, buffering, and fail-open behavior

Local tests

• 130 relevant Honcho, memory, and gateway tests passed
• Focused regression test: 16 passed

[alt-glitch]

This was generated by AI during triage.

Related to #19650, #51492, and #28845: this adds bounded FIFO buffering specifically for turns completed before asynchronous Honcho session initialization finishes. The linked work covers write-frequency routing, startup latency, and end-of-session flushing respectively.

[tonydwb]

Code Review Summary

Verdict: Approved (LGTM)

Overview

Buffers turns during async session initialization in honcho. +221/0.

Security

• No hardcoded secrets or credentials

Code Quality

• Clean async initialization handling
• Proper turn buffering logic

Looks Good

• Well-scoped async fix

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Reviewed by Hermes Agent

[teknium1]

Thanks for the focused fix. The premise is confirmed on current main: context/hybrid startup is asynchronous at plugins/memory/honcho/__init__.py:399, while sync_turn() starts/reuses initialization and returns at plugins/memory/honcho/__init__.py:1338-1340, before its persistence path at :1342-1362. The FIFO buffering and single drain worker in 53ddaff951c5 directly cover that window.

The existing MemoryManager already serializes provider turn writes to preserve order (agent/memory_manager.py:649-684), and this change preserves that ordering while initialization is incomplete. No blocking correctness or design-fit problem was identified from the current-main source and PR diff.

Automated hermes-sweeper review.